- General and Mild Nickel-Catalyzed Cyanation of Aryl/Heteroaryl Chlorides with Zn(CN)2: Key Roles of DMAP
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A new and general nickel-catalyzed cyanation of hetero(aryl) chlorides using less toxic Zn(CN)2 as the cyanide source has been developed. The reaction relies on the use of inexpensive NiCl2·6H2O/dppf/Zn as the catalytic system and DMAP as the additive, allowing the cyanation to occur under mild reaction conditions (50-80 °C) with wide functional group tolerance. DMAP was found to be crucial for successful transformation, and the reaction likely proceeds via a Ni(0)/Ni(II) catalysis based on mechanistic studies. The method was also successfully extended to aryl bromides and aryl iodides.
- Zhang, Xingjie,Xia, Aiyou,Chen, Haoyi,Liu, Yuanhong
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supporting information
p. 2118 - 2121
(2017/04/27)
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- Synthesis of tetramethylammonium phenyltrialkylborate salts by the addition of alkyllithium reagents to a triorganylborane or organoboranylhalides
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Several new tetraorganylborate salts have been synthesized by the addition of alkyl or phenyllithium reagents to a triorganylborane or organoboranylhalides. The chemical structure of the borates was confirmed by 1H, 13C NMR and IR spectroscopic measurements and elemental analysis. Solubility, spectroscopic and electrochemical properties of these salts have been investigated as well. The structures of the phenyltrialkylborates were varied systematically to control their oxidation potential. These compounds are the trimethyl-, triethyl-, n-tributyl- and sec-tributylborate derivatives and form a series of substituted phenyltrialkylborates containing either electron-withdrawing or electron-donating substituents in the para position of phenyl ring. The oxidation potential of these borates has been found to be a function of Hammett constant.
- Pietrzak, Marek,Jdrzejewska, Beata
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experimental part
p. 2135 - 2141
(2011/06/20)
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- Relative basicities of ortho-, meta-, and para-substituted aryllithiums
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(Chemical Equation Presented) The relative basicities of aryllithiums bearing methoxy, chlorine, fluorine, trifluoromethyl and trifluoromethoxy substituents at the ortho, meta, and para positions have been assessed. To this end, two aryllithiums of compar
- Gorecka-Kobylinska, Joanna,Schlosser, Manfred
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experimental part
p. 222 - 229
(2009/04/11)
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- Pharmaceutically active compounds
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The present invention relates to a class of melanocortin MCR4 agonists of general formula (I) wherein R1, R2, R3, R4 and R5 are as defined herein and especially to selective MCR4 agonist compounds, to
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Page/Page column 68
(2010/02/13)
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- Dopamine transporter imaging ligand
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The 3α isomer of RTI-55, RTI-352, is an effective in vivo binding ligand that reflects greater selectivity for the dopamine transporter than is observed with RTI-55. In addition, there is also a more rapid achievement of apparent equilibrium in the striat
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Page column 6
(2010/01/30)
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- Dialkyl, Diaryl, and Alkyl Aryl Complexes of Ruthenium(II)
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Whereas HgR2 (R=methyl or aryl) converts trans-(Ru(CO)2Cl2(PMe2Ph)2) exclusively into (Ru(CO)2R(Cl)(PMe2Ph)2) and does not react with cis-(Ru(CO)2Cl2(PMe2Ph)2), LiR reacts with either isomer to yield (Ru(CO)2R2(PMe2Ph)2) and also catalyses conversion of the trans isomer into the cis.The initial attack by R- is belived to be on a carbonyl ligand.Treatment of (Ru(CO)2R(Cl)(PMe2Ph)2) with LiR' yields mixed complexes (Ru(CO)2R(R')(PMe2Ph)2).In all cases the two organic ligands are mutually cis.The dimethyl complex undergoes reversible carbonylation to form mono- and di-acetyl complexes, and (Ru(CO)2Me(Ph)(PMe2Ph)2) also forms an acetyl coplex, but aryl ligands are unaffected by treatment with CO.
- Saunders, David R.,Stephenson, Martin,Mawby, Roger J.
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p. 2473 - 2478
(2007/10/02)
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- Preliminary Studies of the Mechanism of Metal-Halogen Exchange. The Kinetics of Reaction of n-Butyllithium with Substituted Bromobenzenes in Hexane Solution
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Initial measurements of the rate of reaction of bromobenzene with n-butyllithium in hexane solution have shown the exchange to be first order in bromobenzene and first order in n-butyllithium, with an activation energy of 12 kcal mol-1 (52 kJ mol-1).A Hammett relationship for the reaction of substituted bromobenzenes with n-butyllithium suggests negative charge character in the transition state (ρ ca 2).The addition of a Lewis donor (p-methylanisole) to the hexane solution was found to result in an increase in the rate of exchange, but did not affect the Hammett reaction constant.Several transition-state structures are considered; available evidence suggests that the exchange may be concerted, with either a four-centered structure, or SN2-type attack of the n-butyl anion at the bromine of the aryl bromide
- Rogers, Harold R.,Houk, Janette
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p. 522 - 525
(2007/10/02)
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