- Photoinduced oxidation of triphenylphosphine isolated in a low-temperature oxygen matrix
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Photooxidation reactions of triphenylphosphine (Ph3P) monomers isolated in matrices of solid oxygen at 10 K were characterized by means of infrared spectroscopy. Upon UV (λ > 280 nm) irradiation of O2 matrices, ca. 90% of Ph3P was converted to triphenylphosphine oxide (Ph3P{double bond, long}O), with concomitant formation of ozone. In the competing photoreaction, ca. 10% of Ph3P was converted to diphenyl-phenyl-phosphinate, Ph2(Ph-O-)P{double bond, long}O. The interpretation was assisted by theoretical [DFT(B3LYP)/6-31G(d, p)] calculations of vibrational spectra, as well as by comparison with the experimental vibrational data from separate experiments in which monomeric Ph3P and Ph3P{double bond, long}O were isolated in argon and oxygen matrices at 10 K.
- Reva, Igor,Lapinski, Leszek,Nowak, Maciej J.
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Read Online
- A Novel Phosphorus -> Oxygen Phenyl Migration: Triphenylphosphine Dioxide as a Reaction Intermediate
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Treatment of triphenylphosphine with diethyl azodicarboxylate and hydrogen peroxide results in the formation of phenyl diphenylphosphinate; triphenylphosphine dioxide is suggested as an intermediate.
- Itzstein, Mark von,Jenkins, Ian D.
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Read Online
- Electrochemical Enabled Cascade Phosphorylation of N?H/O?H/S?H Bonds with P?H Compounds: An Efficient Access to P(O)-X Bonds
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An electrochemical three component cascade phosphorylation reaction of various heteroatoms-containing nucleophiles including carbazoles, indoles, phenols, alcohols, and thiols with Ph2PH has been established. Electricity is used as the “traceless” oxidant and water and air are utilized as the “green” oxygen source. All kinds of structurally diverse organophosphorus compounds with P(O)-N/P(O)-O/P(O)-S bonds are assembled in moderate to excellent yields (three categories of phosphorylation products, 50 examples, up to 97 % yield). A tentative free radical course is put forward to rationalize the reaction procedure.
- Abdukader, Ablimit,Dong, Xiaojuan,Jin, Weiwei,Liu, Chenjiang,Wang, Bin,Wang, Ruige,Xia, Yu,Xue, Fei,Zhang, Yonghong
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supporting information
p. 14931 - 14935
(2021/10/06)
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- Tf2O/DMSO-Promoted P-O and P-S Bond Formation: A Scalable Synthesis of Multifarious Organophosphinates and Thiophosphates
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A Tf2O/DMSO-based system for the dehydrogenative coupling of a wide range of alcohols, phenols, thiols, and thiophenols with diverse phosphorus reagents has been developed. This metal- and strong-oxidant-free strategy provides a facile approach to a great variety of organophosphinates and thiophosphates. The simple reaction system, good functional-group tolerance, and broad substrate scope enable the application of this method to the modification of natural products and the direct synthesis of bioactive molecules and flame retardants.
- Shen, Jian,Li, Qi-Wei,Zhang, Xin-Yue,Wang, Xue,Li, Gui-Zhi,Li, Wen-Zuo,Yang, Shang-Dong,Yang, Bin
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supporting information
p. 1541 - 1547
(2021/04/05)
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- Palladium-catalyzed solvent-free preparation of arylphosphonates Arp(O)(OAr)2 from (Aro)3p via the Michaelis-Arbuzov rearrangement
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The Pd-catalyzed Michaelis-Arbuzov rearrangement of triaryl phosphites to produce the corresponding arylphosphonates in good to excellent yields is disclosed. In comparison to the traditional methods, this new method is highly atom efficient and is general, as it can be readily extended to aryl phosphonites and phosphinites. A gram-scale reaction of (PhO)3P to PhP(O)(OPh)2 with low loading of the catalyst was also demonstrated to show its potentially practical usefulness. A plausible mechanism is proposed.
- Li, Chunya,Han, Li-Biao
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supporting information
p. 3613 - 3617
(2020/11/03)
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- Base-promoted selective O-phosphorylation of aryl triflates with P(O)-H compounds
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Compared to previous transition metal-catalyzed C-phosphorylation reactions for constructing C–P bonds, in the absence of transition metal catalysts and ligands, a direct O-phosphorylation of aryl triflates selectively occurred with P(O)-H compounds in the presence of a base via the construction of O–P bonds. This transformation proceeds under simple and mild conditions, and provides a new method for the preparation of valuable organophosphoryl compounds from readily available P(O)-H compounds and triflates.
- Wang, Mingyue,Yang, Jia,Wang, Shuai,Zhong, Hong
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supporting information
(2020/05/05)
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- Phosphonate compound, preparation method and application thereof
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The invention provides a phosphonate compound, a preparation method and application thereof. The method includes the steps of: in a nitrogen atmosphere, mixing a P(O)-H compound, an aryl trifluoromethanesulfonate compound, an alkali reagent and an organic solvent, carrying out stirring reaction at 80-130DEG C for 15-24h, and conducting cooling, washing and extraction at the end of reaction to obtain an organic phase; drying and distilling the obtained organic phase to obtain the phosphonate compound; wherein the molar ratio of the P(O)-H compound, the aryl trifluoromethanesulfonate compound and the alkali reagent is 1-3:1:2-3. The method has the advantages of simple and easily available raw materials, simple reaction conditions, wide functional group compatibility, high yield and wide applicability, the structural formula of the obtained phosphonate compound is shown as formula (I) in the specification, and the extraction rate of the phosphonate compound applied to the field of lithiumion extraction is 53% or above.
- -
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Paragraph 0053-0055
(2020/04/02)
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- A phosphoryl radical-initiated Atherton-Todd-type reaction under open air
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A phosphoryl radical-initiated Atherton-Todd-type reaction using air as the radical initiator and CHCl3 as the halogenating reagent for the phosphorylation of alcohols, phenols, and amines has been developed. This novel transformation provides a highly efficient route to important phosphinates, phosphinic amides, and phosphoramidates in up to 99% yield with a broad substrate scope under very mild conditions (48 examples).
- Ou, Yingcong,Huang, Yuanting,He, Zhenlin,Yu, Guodian,Huo, Yanping,Li, Xianwei,Gao, Yang,Chen, Qian
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supporting information
p. 1357 - 1360
(2020/02/11)
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- Highly Efficient and Convenient Access to Phosphinates via CHCl3-Assisted Direct Phosphorylation between R2P(O)H and ROH by Phosphonium Salt Catalysis
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A mild, efficient, convenient and scalable method to synthesize phosphinates via direct phosphorylation between R2P(O)H and ROH was developed. All aromatic substrates completed this transformation with excellent yields (up to 98 %), and preliminary mechanistic studies suggest that a carbene-involving process from CHCl3 to CH2Cl2 facilitates the phosphorylation.
- Jiang, Zhiyu,Wang, Tianli,Yu, Xiaojun,Zhang, Hong-Su,Zhang, Song
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supporting information
(2020/05/25)
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- Preparation method of compound containing P-O bond or P-S bond
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The invention discloses a preparation method of a compound containing a P-O bond or a P-S bond. The method comprises the following steps: a compound containing hydroxyl or sulfydryl and a phosphorus reagent are taken as initial raw materials; then, the initial raw materials are put into an inert gas atmosphere; and under the action of trifluoromethanesulfonic anhydride (Tf2O) and dimethyl sulfoxide (DMSO), the compound containing hydroxyl or sulfydryl, the phosphorus reagent, the trifluoromethanesulfonic anhydride and the dimethyl sulfoxide in a molar ratio of (1-5): (1-2.5): (2-3): 2 react inan organic solvent at the reaction temperature of 25-100 DEG C for 6-20 hours to obtain the compound with the structural general formula (I). The reagents used in the method are low in toxicity and environmentally friendly, and use of precious metal catalysts high in price and toxicity is avoided. The reagents trifluoromethanesulfonic anhydride (Tf2O) and dimethyl sulfoxide (DMSO) used in the method are low in toxicity and very low in cost, so that the method is green, environment-friendly, high in economy and suitable for large-scale production.
- -
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Paragraph 0287-0291
(2020/09/12)
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- A scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with RSH/ROH
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A practical, scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with thiols, phenols and alcohols in both an undivided cell and a continuous-flow setup is disclosed. Its broad substrate scope (>50 examples), good functional-group tolerance and scalability (>10 g) show potential for practical synthesis. A preliminary mechanistic study suggests that the phosphorus radicals are involved in the catalytic cycle.
- Li, Yujun,Yang, Qi,Yang, Liquan,Lei, Ning,Zheng, Ke
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supporting information
p. 4981 - 4984
(2019/05/21)
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- DCC-assisted direct esterification of phosphinic and phosphoric acids with O-nucleophiles
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A novel and efficient dicyclohexylcarbodiimide-promoted protocol for the selective and controllable esterification of P(O)OH compounds using O-nucleophiles (alcohols and phenols) as efficient esterification reagents is described. This method features a high efficiency and good functional-group tolerance, meaning a simple way to synthesize a broad spectrum of phosphinic and phosphoric acid esters from basic starting materials with moderate to excellent yields.
- Xiong, Biquan,Wang, Gang,Zhou, Congshan,Liu, Yu,Li, Jiandong,Zhang, Pangliang,Tang, Kewen
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supporting information
p. 239 - 244
(2017/11/20)
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- Method for synthesis of organophosphorus compound by photo-induced iodine catalyzed Atherton-Todd reaction
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The invention belongs to the technical field of organic synthesis, discloses a method for synthesis of organophosphorus compound by photo-induced iodine catalyzed Atherton-Todd reaction. The method comprises the following steps: a compound shown as formula II and a nucleophilic reagent are subjected to reaction for 24 hours in a dichloromethane solvent, an oxygen atmosphere, under irradiation condition of room temperature and the action of a halogenated reagent I2, then the organophosphorus compound shown as the formula II is obtained through washing, drying, separating and purifying. According to the the method provided by the invention, compared with traditional Atherton-Todd reaction, no catalysis of metal is needed,no addition of alkali is needed, reaction environment such as metal, high temperature and strong base is replaced, a series of organophosphorus compounds can be synthesized by catalyzing a variety of substrates under the irradiation condition of room temperature, and hasthe advantages of good universality, short reaction time and higher yield.
- -
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Paragraph 0021
(2018/12/14)
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- Method for preparing organophosphate compound through efficient esterification of P(O)-OH-containing compound and phenol
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The invention provides a method for preparing an organophosphate compound through efficient esterification of a P(O)-OH-containing compound and phenol. The method realizes efficient and highly selective synthesis of organophosphate derivatives containing
- -
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Paragraph 0016; 0017; 0018; 0019; 0020; 0021
(2017/09/01)
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- CDI-promoted direct esterification of P(O)-OH compounds with phenols
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A novel and efficient N,N′-carbonyl diimidazole-catalyzed protocol for the direct esterification of P(O)-OH compounds using phenols as efficient esterification reagents is illustrated. It is a simple way to synthesis a broad spectrum of functionalized O-aryl phosphinates, phosphonates, and phosphates from basic starting materials with moderate to excellent yields.
- Xiong, Biquan,Hu, Chenghong,Li, Haotian,Zhou, Congshan,Zhang, Pangliang,Liu, Yu,Tang, Kewen
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supporting information
p. 2482 - 2486
(2017/05/31)
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- Method for preparing phosphinic acid ester/phosphorous acid ester/phosphoric acid ester from P(O)-OH compound and aryl boronic acid
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The invention provides a method for high-selectivity synthesis of phosphinic acid ester/phosphorous acid ester/phosphoric acid ester derivatives containing different substituted functional groups; a metal salt is used as a catalyst, a P(O)-OH-containing compound and aryl boronic acid are used as reactants, and an alkali, an additive and an organic solvent are added into the reaction system. The method has the advantages that the catalyst is cheap and easy to obtain; the reaction conditions are mild, and the method is safe and reliable; the selectivity of the obtained target product is close to 100%, and the yield is as high as 90% or more. The method solves the deficiency that traditional synthetic phosphinic acid ester/phosphorous acid ester/phosphoric acid ester compounds have poor reaction selectivity, complex reaction steps and low yield and need to use reagents harmful to the environment, and has a good prospect in industrial application. The invention also provides the corresponding phosphinic acid ester/phosphorous acid ester/phosphoric acid ester derivatives correspondingly containing different substituted functional groups.
- -
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Paragraph 0017
(2016/10/10)
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- Kinetic study on nucleophilic substitution reactions of aryl diphenylphosphinates with butane-2,3-dione monoximate and aryloxide anions: Reaction mechanism and origin of the α-effect
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A kinetic study is reported for nucleophilic substitution reactions of X-substituted-phenyl diphenylphosphinates (3a-3f) with butane-2,3-dione monoximate (Ox-) and a series of Y-substituted-phenoxide (Y-PhO-) ions in 50 mol % H2O/50 mol % DMSO at 25.0 ± 0.1°C. The reactions of 3a-3f with Ox- and 4-chlorophenoxide (4-ClPhO-) result in linear Br?nsted-type plots with βlg = -0.70 and -0.64, respectively, a typical βlg value for reactions reported previously to proceed through a concerted mechanism. The Br?nsted-type plots for the reactions of 4-chloro-2-nitrophenyl diphenylphosphinate (3a), 4-nitrophenyl diphenylphosphinate (3b), and 4-acetylphenyl diphenylphosphinate (3d) with Y-PhO- are also linear with βnuc = 0.15-0.35. The current reactions have been concluded to proceed through a concerted mechanism in which the bond formation is much less advanced than the bond rupture in the TS on the basis of the βlg and βnuc values. The α-effect observed in this study is very small (i.e., the kOx-/kp-ClPhO- ratio=4.61-43.5) and is independent of the leaving-group basicity. It has been concluded that the α-effect shown by Ox- in the current reactions is mainly due to desolvation of Ox- in the reaction medium (ground-state contribution) rather than stabilization of the transition-state (TS contribution) on the basis of the kinetic results.
- Um, Ik-Hwan,Han, Jeong-Yoon
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p. 1180 - 1184
(2016/08/12)
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- Efficient asymmetric synthesis of structurally diverse p-stereogenic phosphinamides for catalyst design
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The use of chiral phosphinamides is relatively unexplored because of the lack of a general method for the synthesis. Reported herein is the development of a general, efficient, and highly enantioselective method for the synthesis of structurally diverse P-stereogenic phosphinamides. The method relies on nucleophilic substitution of a chiral phosphinate derived from the versatile chiral phosphinyl transfer agent 1,3,2-benzoxazaphosphinine-2-oxide. These chiral phosphinamides were utilized for the first synthesis of readily tunable P-stereogenic Lewis base organocatalysts, which were used successfully for highly enantioselective catalysis.
- Han, Zhengxu S.,Zhang, Li,Xu, Yibo,Sieber, Joshua D.,Marsini, Maurice A.,Li, Zhibin,Reeves, Jonathan T.,Fandrick, Keith R.,Patel, Nitinchandra D.,Desrosiers, Jean-Nicolas,Qu, Bo,Chen, Anji,Rudzinski, Diandra M.,Samankumara, Lalith P.,Ma, Shengli,Grinberg, Nelu,Roschangar, Frank,Yee, Nathan K.,Wang, Guijun,Song, Jinhua J.,Senanayake, Chris H.
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supporting information
p. 5474 - 5477
(2015/04/27)
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- Copper-catalyzed direct esterification of P(O)-OH compounds with phenols
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A novel copper-catalyzed method for the direct esterification of P(O)-OH compounds using phenols as efficient esterification reagents is illustrated. It is a simple way to generate a broad spectrum of functionalized O-aryl phosphinates, phosphonates, and phosphates from basic starting materials with moderate to excellent yields.
- Xiong, Biquan,Zeng, Kui,Zhang, Shanshan,Zhou, Yongbo,Au, Chak-Tong,Yin, Shuang-Feng
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supporting information
p. 9293 - 9298
(2015/11/27)
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- Chemoselective reduction of the phosphoryl bond of O-alkyl phosphinates and related compounds: An apparently impossible transformation
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A method is reported for the phosphoryl bond cleavage of O-alkyl phosphinates, phosphinothioates and certain phosphonamidates to furnish the corresponding P(iii) borane adducts. The two-step procedure relies upon initial activation of the phosphoryl bond with an alkyl triflate, followed by reduction of the resulting intermediate using lithium borohydride.
- Kenny, Niall P.,Rajendran, Kamalraj V.,Gilheany, Declan G.
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p. 16561 - 16564
(2015/11/18)
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- Direct aerobic oxidative esterification and arylation of P(O)-OH compounds with alcohols and diaryliodonium triflates
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Copper-catalyzed aerobic oxidative esterification of P(O)-OH compounds is achieved using alcohols as efficient esterification reagents, giving the expected products with good to moderate yields. Furthermore, it is shown that the arylation of P(O)-OH compounds proceeds efficiently to produce the corresponding products via the treatment of diaryliodonium triflates under mild reaction conditions. It is a simple way to produce a broad spectrum of functionalized phosphinates, phosphonates, and phosphates from basic starting materials with good to excellent yields. The protocol is convenient for practical application. A plausible mechanism has been proposed for the reaction.
- Xiong, Biquan,Feng, Xiaofeng,Zhu, Longzhi,Chen, Tieqiao,Zhou, Yongbo,Au, Chak-Tong,Yin, Shuang-Feng
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p. 537 - 543
(2015/04/14)
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- Chloroform-based Atherton-Todd-type reactions of alcohols and thiols with secondary phosphine oxides generating phosphinothioates and phosphinates
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Chloroform-based Atherton-Todd-type reactions of alcohols and thiols with secondary phosphine oxides, generating phosphinothioates and phosphinates, respectively, are described. Various valuable phosphinothioates and phosphinates including those with functional groups are readily prepared under mild reaction conditions.
- Li, Shan,Chen, Tieqiao,Saga, Yuta,Han, Li-Biao
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p. 71544 - 71546
(2015/09/08)
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- The α-effect in nucleophilic substitution reactions of Y-substituted-phenyl diphenylphosphinates with HOO- and OH -
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Second-order rate constants (kHOO-) for the nucleophilic substitution reactions of Y-substituted-phenyl diphenylphosphinates (4a-4i) with HOO- in H2O have been measured spectrophotometrically. The a-nucleophile
- Hong, Hyo-Jeong,Bae, Ae Ri,Um, Ik-Hwan
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p. 2251 - 2255
(2013/09/24)
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- Kinetics and reaction mechanism for alkaline hydrolysis of Y-substituted-phenyl diphenylphosphinates
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The second-order rate constants (kOH-) for the reactions of Y-substituted-phenyl diphenylphosphinates (4a-4i) with OH- in H 2O at 25.0 ± 0.1 °C have been measured spectrophotometrically. Comparison of kOH- with kEtO- (the second-order rate constants for the corresponding reactions with E tO- in ethanol) has revealed that EtO- is less reactive than OH- although the former is ca. 3.4 pKa units more basic than the latter, indicating that the reactivity of these nucleophiles is not governed by their basicity alone. The Bronsted-type plot for the reactions of 4a-4i with OH- is linear with βlg = -0.36. The Hammett plot correlated with σ- constants results in a slightly better correlation than that correlated with σo constants but exhibits many scattered points. In contrast, the Yukawa-Tsuno plot for the same reactions exhibits an excellent linear correlation with ρ = 0.95 and r = 0.55. The r value of 0.55 implies that a negative charge develops partially on the O atom of the leaving group. Thus, the reactions of 4a-4i with OH- have been concluded to proceed through a concerted mechanism. Copyright
- Hong, Hyo-Jeong,Lee, Jieun,Bae, Ae Ri,Um, Ik-Hwan
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p. 2001 - 2005
(2013/09/02)
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- Kinetics and mechanism of the anilinolyses of aryl dimethyl, methyl phenyl and diphenyl phosphinates
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The reactions of Z-aryl dimethyl (1), methyl phenyl (2), and diphenyl (3) phosphinates with X-anilines in dimethyl sulfoxide at 60.0 °C are studied kinetically. Kinetic results yield the primary normal deuterium kinetic isotope effects (DKIEs) involving deuterated aniline (XC6H4ND 2) nucleophiles, kH/kD = 1.03-1.17, 1.15-1.29, and 1.24-1.51, and the cross-interaction constants (CICs), ρXZ = 0.37, 0.34, and 0.65 for 1, 2, and 3, respectively. The steric effects of the ligands (R1 and R2) on reaction rates play a role, but are relatively much smaller compared to other phosphinate systems. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed on the basis of the CICs positive signs. The dominant frontside nucleophilic attack through a hydrogen-bonded, four-center-type transition state is proposed on the basis of primary normal DKIEs and large magnitudes of the CICs for 2 and 3, while both frontside and backside attack are proposed on the basis of relatively small primary normal DKIEs for 1.
- Dey, Nilay Kumar,Kim, Chan Kyung,Lee, Hai Whang
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supporting information; experimental part
p. 717 - 724
(2011/04/16)
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- Oxidative transition-metal-free cross-coupling of secondary phosphine chalcogenides and alcohols or phenols: A facile, expedient synthesis of phosphinochalcogenoic O-esters
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Oxidative transition-metal-free, cross-coupling reaction between secondary phosphine chalcogenides and alcohols or phenols proceeds in the carbon tetrachoride/triethylamine system under mild conditions (20-52 C, 1-12 h) to give phosphinochalcogenoic O-est
- Gusarova, Nina K.,Volkov, Pavel A.,Ivanova, Nina I.,Larina, Ludmila I.,Trofimov, Boris A.
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experimental part
p. 3723 - 3729
(2011/12/21)
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- Rationale behind the resistance of dialkylbiaryl phosphines toward oxidation by molecular oxygen
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Electron-rich dialkylbiaryl phosphines, which comprise a common class of supporting ligands for Pd-catalyzed cross-coupling reactions, are highly resistant toward oxidation by molecular oxygen. Presented herein are possible reasons why this class of phosphine ligands manifests this property. Experimental and theoretical data suggest that the two alkyl substituents on the phosphorus center and the 2′ and 6′ positions of the biaryl backbone play an important role in inhibiting oxidation of this class of ligands.
- Barder, Timothy E.,Buchwald, Stephen L.
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p. 5096 - 5101
(2008/02/02)
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- Rapid and high yield oxidation of phosphine, phosphite and phosphinite compounds to phosphine oxides, phosphates and phosphinates using hypofluorous acid-acetonitrile complex
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The hypofluorous acid acetonitrile complex was used as a mild, rapid, and effective agent to oxidize a wide variety of phosphines, phosphites and phosphinites to the corresponding phosphine oxide, phosphate and phosphinate compounds.
- Peng, Weimin,Shreeve, Jean'Ne M.
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p. 1054 - 1056
(2007/10/03)
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- Mixed anhydrides: Key intermediates in carbamates forming processes of industrial interest
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Mixed anhydrides of carbonic acid with phosphonic or carbamic acid, are mimic of relevant biological systems, and behave as key intermediates in transesterification processes that afford carbamates of industrial interest. They are formed in the phosphonic acids mediated or direct transesterification reaction of organic carbonates with amines to afford carbamates and have been isolated and characterised in the solid state and solution. Their conversion into the products has been demonstrated to occur with high regioselectivity. The application of such intermediates in some synthetic processes is discussed.
- Aresta, Michele,Dibenedetto, Angela
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p. 685 - 690
(2007/10/03)
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- Reaction of aromatic diamines with diphenylcarbonate catalyzed by phosphorous acids: A new clean synthetic route to mono- and dicarbamates
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In the presence of organophosphorus acids [Ph2P(O)OH, (PhO)2P(O)OH, (BuO)2P(O)OH, (BuO)P(O)(OH)2], aromatic diamines, such as 4,4'- methylendianiline (MDA) or 2,4-diaminotoluene (TDA), react with diphenylcarbonate (DPC) to afford in a very selective way mono- and dicarbamate phenyl esters. The carbamation process is strongly influenced by the temperature and solvent. The influence of both these factors on carbamate yield and selectivity has been investigated and we present in this study the kinetics of formation of both mono- and dicarbamate esters.
- Aresta, Michele,Dibenedetto, Angela,Quaranta, Eugenio
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p. 14145 - 14156
(2007/10/03)
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- Solvent effects on reactions of hydroxide and oximate ions with phosphorus(V) esters
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Second-order rate constants of reactions of OH-, 2,3-butanedionemonooximate and 2-hydroxybenzaldoximate ions with aryl phosphate, phosphinate and thioarylphosphinate esters go through minima with decreasing water content of aqueous acetonitrile, tert-butyl alcohol and N-methyl-2-pyrrolidone. For reactions in H2O-MeCN the solvent effects are analyzed in terms of activity coefficients of the anionic nucleophiles and transition states. In the drier solvents partial desolvation of the nucleophiles increases rates. Nucleophilicities of several oximates and inorganic anions are compared in water.
- Bunton, Clifford A.,Gillitt, Nicholas D.,Kumar, Anurag
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p. 221 - 228
(2007/10/03)
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- Phosphadioxirane Intermediates in the Reaction of Singlet Oxygen with Phosphites and Phosphines
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Intermediates in the singlet oxygen reaction of phosphites and phosphines have been studied by trapping and tracer experiments.Trapping study with diphenyl sulfoxide revealed that the added substrate and phosphite are competing toward the same intermediate.The relative reactivity of (BuO)3P/Ph2S/Ph2SO = 300:4:1 and the negative ρ-value of -0.63 for diphenyl sulfoxides are not consistent with 1,3-dipolar phosphine peroxides, but suggest electrophilic O-transfers by cyclic phosphadioxiranes.Intermediacy of phosphadioxiranes was supported by an 18O-tracer study on the formation of rearranged diphenylphosphinate from 1O2 and triphenylphosphine.Theoretical calculations also supported the dioxirane intermediate by predicting no existence of 1,3-dipolar peroxide.
- Tsuji, Shoei,Kondo, Masaaki,Ishiguro, Katsuya,Sawaki, Yasuhiko
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p. 5055 - 5059
(2007/10/02)
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- The Phenomenology of Differently Constructed Broensted-type Plots
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Two different methodologies for the construction of Broensted-type plots are compared; curved plots using the traditional approach and linear plots by a novel approach are obtained for the reaction of phenoxides with p-nitrophenyl diphenylphosphinate in dimethyl sulfoxide-water media at 25 deg C.
- Buncel, E.,Tarkka, R.,Hoz, S.
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p. 109 - 110
(2007/10/02)
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- Manganese(II) Complexes containing the Phenyl Diphenylphosphinate Ligand and Their Reactivity with SO2; the First Crystallographically Characterised Complex containing a Phosphinate Ligand
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Complexes of manganese(II) with the rarely studied phenyl diphenylphosphinate ligand have been synthesised.Their isolation is solvent dependent: the bis(ligand) complexes, 2X2> (X=Cl, Br, I or NCS), are readily isolated, but the tetrakis de
- Abbas, Shaker,Beagley, Brian,Godfrey, Stephen M.,Kelly, David G.,McAuliffe, Charles A.,Pritchard, Robin G.
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p. 1915 - 1920
(2007/10/02)
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- Solvent modulation of metal-ion effects in nucleophilic displacement at a phosphorus center
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The reaction of alkali-metal phenoxides with p-nitrophenyl diphenylphosphinate shows strikingly different behaviour in ethanol and tetraglyme solvents.The overall rate of reaction is approximately 100,000 times greater in tetraglyme and the effects of alkali-metal counterions on rate are different in their nature (catalysis or inhibition) as well as in their extent in the two solvents.These observations are discussed in terms of the effects of hydrogen-bonding interactions and other specific solvent interactions on the ground state and the transition state of the reaction.
- Buncel, E.,Dunn, E. J.,Truong, Ng. van,Pregel, M. J.,Bannard, R. A. B.,Purdon, J. G.
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p. 1591 - 1596
(2007/10/02)
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- The effect of alkali metal ions on the reaction of 4-nitrophenyl diphenylphosphinate with aryloxides in ethanol
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Rate constants have been measured for the reaction of p-nitrophenyl diphenylphosphinate with aryloxides in ethanol. The reactivity of the less basic phenoxide decreases in the order K+-18-crown ether-6 > K+ > Na+ > Li+, which leads a conclusion that alkali metal-bound aryloxides are less reactive than the dissociated ones in the present system.
- Um,Yong,Kwon,Ahn,Lee
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p. 6483 - 6486
(2007/10/02)
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- Reaction of Dichlorotriphenylphosphorane with Bis(trimethylsilyl) Peroxide. A new Method for the Formation of Electrophilic Chlorine Source.
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Reactions of dichlorotriphenylphosphorane with bis(trimethylsilyl) peroxide in the presence of some organic compounds have been found to give chlorinated products.Aromatic hydrocarbons bearing electron-donating substituents give the corresponding monochloroarenes, while an enol silyl ether is converted into α-chloro-ketone.The mechanism is briefly discussed.
- Shibata, Kazusato,Itoh, Yukinori,Tokitoh, Norihiro,Okazaki, Renji,Inamoto, Naoki
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p. 3749 - 3751
(2007/10/02)
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- (Diphenylphosphinoyl)oxyl: An Extremely Reactive Oxygen-Centered Radical
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The title radical, Ph2P(O)O., has been generated by laser flash photolysis (LFP) of the peroxide 2 (1) in CH3CN solution.It has a broad, structureless absorption extending from 400 to beyond 800 nm.Absolute bimolecular rate constants k for its reactions with various organic substrates have been measured by LFP.It has been found that Ph2P(O)O. is more reactive in hydrogen abstraction (e.g., cyclohexane, k= 2.4x1E8 M-1s-1) and addition (e.g., benzene, k= 9.1x1E8 M-1s-1) than any other organic oxygen-centered radical.Only HO. is (generally) more reactive.Although Ph2P(O)O. could not be directly detected by EPR spectroscopy , it was successfully spin-trapped with a nitrone and with alkenes and alkynes.The formation of Ph2P(O)O. in the photodecomposition but not in the thermal decomposition of 1 is supported by 31P NMR analyses of reaction products.Semiempirical AM1-PM3 calculations on H2P(O)O. are also reported.
- Korth, H.-G.,Lusztyk, J.,Ingold, K.U.
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p. 624 - 631
(2007/10/02)
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- Metal ion catalysis in nucleophilic displacement reactions at carbon, phosphorus, and sulfur centers. II. Metal ion catalysis in the reaction of p-nitrophenyl diphenylphosphinate with alkali metal phenoxide in ethanol
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The reactions of p-nitrophenyl diphenylphosphinate (1) with lithium, sodium, potassium, and benzyltrimethylammonium phenoxides (BTMAOPh) have been studied by spectrophotometric techniques in anhydrous ethanol at 25 deg C.The reactivity (kobs) of the alkali metal phenoxides increases in the order BTMAOPh cryptand for Na+, and cryptand for Li+, to each of the alkali metal phenoxide reactions resulted in a decrease in rate, indicating catalysis by the alkali metal ions.The kinetic data are analyzed to obtain specific rate coefficients of reactions of phenoxide and ethoxide as the dissociated ions and as alkali metal - phenoxide ion pairs.Reactivities follow the order kPhOM > kPhO-; kEtOM > kEtO-; kEtO- > kPhO-; KEtOM > kPhOM.A mechanism is proposed in which the ion-paired metal phenoxide is more reactive towards the substrate than is the dissociated phenoxide.Analysis of the data in terms of initial state and transition state interactions with metal ions indicates that the increased reactivity of the ion-paired species results from greater stabilization of the negatively charged transition state relative to stabilization of the ion-paired nucleophile.
- Dunn, Edward J.,Moir, Robert Y.,Buncel, Erwin,Purdon, J. Garfield,Bannard, Robert A. B.
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p. 1837 - 1845
(2007/10/02)
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- Metal ion catalysis in nucleophilic displacement reactions at carbon, phosphorus, and sulfur centers. III. Catalysis vs. inhibition by metal ions in the reaction of p-nitrophenyl benzenesulfonate with ethoxide
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The rate of the nucleophilic displacement reaction of p-nitrophenyl benzenesulfonate (1) with alkali metal ethoxides in ethanol at 25 deg C has been studied by spectrophotometric techniques.For lithium ethoxide, sodium ethoxide, potassium ethoxide, and cesium ethoxide, the observed rate constants increase in the order LiOEt NaOEt CsOEt KOEt.The effect of added crown ether and cryptand complexing agents was also investigated.Addition of complexing agent to the reaction of KOEt results in the rate decreasing to a minimum value corresponding to the reaction of free ethoxide.Conversely, addition of complexing agent ot the reaction of LiOEt results in the rate increasing to a maximum value that is identical to the minimum value seen in the reaction of KOEt in the presence of excess complexing agent.In complementary experiments, alkali metal ions were added in the form of unreactive salts.Addition of a K+ salt to the reaction of KOEt increases the reaction rate, while addition of a Li+ salt to the reaction of LiOEt decreases the rate.The involvment of metal ions in the reaction of 1 is proposed to occur via reactive alkali metal - ethoxide ion pairs.The kinetic data are analyzed in terms of an ion pairing treatment that allows the calculation of second-order rate constants for free ethoxide and metal-ethoxide ion pairs. the kinetic data are analyzed in terms of an ion pairing treatment that allows the calculation of second-order rate constants for free ethoxide and metal-ethoxide ion pairs; the rate constants increase in the order LIOEt EtO- NaOEt CsOEt KOEt.Thus, Li+ is an inhibitor of the reaction of ethoxide with 1, while the other metals ions studied are all catalysts.Equilibrium constants for the association of the various metal ions with the transition state are calculated using a thermodynamic cycle, and are compared to association of the various metal ions with the transition state are calculated using a thermodynamic cycle, and are compared to association constants in the ground state.Consistent with the observed kinetic results, Li+ is found to stabilize the ground state more than the transition state, while Na+, K+, and Cs+ all stabilize the transition state more than the ground state. the trend in the magnitude of the transition state stabilization is interpreted in terms of interactions of the transition state with bare or solvated metal ions.It is concluded that the transition state for the reaction of 1 with ethoxide forms solvent separated ion pairs with alkali metal ions.Analogous data were available for the reaction of p-nitrophenyldiphenylphosphinate (2) with ethoxides, where Li+, Na+, K+, and Cs+ all function as catalysts, and the results are analyzed as above.In contrast to the sulfonate system, it is proposed that the phosphinate transition state forms contact ion pairs with alkali metal ions.The difference is attributed to a greater localization of negative ...
- Pregel, Marko J.,Dunn, Edward J.,Buncel, Erwin
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p. 1846 - 1858
(2007/10/02)
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- Solvent effect on ground-state versus transition-state stabilization by metal ions. Contrasting metal ion behaviour in tetraglyme and ethanol for nucleophilic displacement at a phosphorus centre
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The rate of reaction of p-nitrophenyl diphenylphosphinate with alkali metal phenoxide follows the order LiOPh> KOPh in ethanol as solvent but in tetraglyme the reactivity order is KOPh? LiOPh and the reaction rate is much faster, which is accounted for on the basis of differing stabilization of the ground-state through hydrogen-bonding and of the transition-state by interaction with M+ in the two solvents.
- Buncel,Dunn,Van Truong,Bannard,Purdon
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p. 6513 - 6516
(2007/10/02)
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- A NOVEL SUBSTITUENT EFFECT ON 31P NMR CHEMICAL SHIFTS IN THE ARYL DIPHENYLPHOSPHINATE SERIES
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The 31P NMR chemical shifts of a series of meta- and para-substituted phenyl diphenylphosphinates, Ph2P(O)OC6H4-X, have been determined.The δ 31P values exhibit an increasing downfield trend as the electron-withdrawing properties of the substituent X become greater and a reasonable correlation between δ 31P and Hammett-Taft substituent constants is obtained.This trend is opposite to that exhibited in several families of compounds of the type ArP(O)Y2, where δ 31P values show an increasing upfield trend as the electron-withdrawing ability of the substituent in Ar is increased.The results are explained by proposing varying degrees of d-orbital occupancy in the phosphorous-oxygen bonds (P-OAr and P=O) in the series of compounds as a factor influencing 31P chemical shifts.
- Hoz, S.,Dunn, E. J.,Buncel, E.,Bannard, R. A. B.,Purdon, J. G.
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p. 321 - 326
(2007/10/02)
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- PHOSPHORORGANISCHE VERBINDUNGEN 103. Die ozonolytische Desulfurierung von Thiophosphorylverbindungen: P=S -> P=O
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The sulfur atom in thiophosphorylgroups P=S is exchanged by oxygen with retention of configuration according to (1) and (2) as a result of an interaction of the P=S groups with ozone (Table 1 and 2).In dithiophosphinicacidesters only the thionosulfur is easily replaced by oxygen using ozone.The absolute configuration of the enantiomeric methyl-phenyl-phosphinicacid-p-nitrophenylesters 7 an 8 is controlled on the basis of the reaction circle (4).Serine enzymes are blocked by the phosphinicacidesters 7 and 8 by a rate factor of about 60 faster than by the corresponding thionophosphinicacidesters 5 and 6.The phosphinicacidesters 7 (and 8) have a high O-selectivity in competing reactions (7:n-BuOH:n-BuNH2 = 1:1:1) in contrast to the thionophosphinicacidesters 5 (and 6) with no selectivity (ester:amide = 4:6).
- Horner, L.,Flemming, H. W.
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p. 245 - 252
(2007/10/02)
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- PHOSPHORORGANISCHE VERBINDUNGEN 96. DIE SELECTIVE VERKNUEPFUNG BIOLOGISCH WICHTIGER FUNKTIONELLER GRUPPEN MIT PHOSPHORORGANISCHEN SAEUREN
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Derivatives of phosphinic, phosphonic, and phosphoric acids of the general type R1R2P(O)X show selectivity in their reactions with nucleophiles RYH (R = n-C4H9; Y = O, NR or S) according the Eq. (1); the selectivity depends on the nature of the leaving group (X = Cl, F, CN, N3 or OC6H4NO2(p)) and the base used.The nature of the ligands R1 and R2, exert a comparatively minor influence on the reaction.Method: (a) The phosphylating agent R1R2P(O)X was allowed to react with mixture of two nucleophiles RYH and RY'H in competition (Reagent ratio 1:1:1).The product mixture (R1R2P(O)YR + R1R2P(O)Y'R was then analyzed. (b) Compounds of the type HY-CH2-CH2-Y'H (serine-n-butylamide L-cysteinmethylester) were reacted with the phosphylating agent R1R2P(O)X (reagent ratio 1:1) according the Eqs. (3) and (4) respectively.The products were isolated, identified and the yields quantitatively determined.Results: For X = F, CN, OC6H4NO2 (p), the O-ester is formed virtually exclusively.For X = Cl, only amides are formed.Azides (X = N3) show no selectivity.In competition reactions using n-butylamine and n-butylthiol, the organophosphorus chlorides (X = Cl) were found to be N-selective,, whereas the corresponding cyanides (X = CN) were S-selective.In competition reactions using n-butanol and n-butylthiol, the organophosphorus fluorides (X = F) p-nitrophenylesters (X = OC6H4NO2(p)) and cyanides (X = CN) were all O-selective.
- Horner, L,Gehring, R.
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p. 157 - 176
(2007/10/02)
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