446-49-1Relevant articles and documents
Enantioselective hydroformylation of 2- and 4-substituted styrenes with PtCl2[(R)-BINAP] + SnCl2‘in situ’ catalyst
Pongrácz, Péter,Kollár, László
, p. 118 - 123 (2016/10/25)
Two sets of styrenes possessing various substituents either in ortho or para position were hydroformylated in the presence of ‘in situ’ catalyst formed from PtCl2[(R)-BINAP] and tin(II) chloride. The reversal of the absolute configuration of the preferred enantiomers was observed using both sets of substrates by the variation of the reaction temperature in the range of 40–100 °C. In case of the 4-substituted styrenes, the reversal temperature of the enantioselectivity shows correlation with the Hammett substituent constants, i.e., with the electron donor or electron acceptor properties of the para-substituents. This phenomenon was explained by the reversible formation of the Pt-branched alkyl intermediates, leading to the corresponding (R)- and (S)-enantiomers of 2-arylpropanals. Strong substituent effect on the regioselectivity was observed in the hydroformylation of 2-substituted styrenes: the presence of substituents characterised by larger steric parameter resulted in the highly favoured formation of the linear aldehyde. For instance, regioselectivities of 45%, 22% and 7% towards branched aldehyde were obtained with styrene, 2-fluoro- and 2-bromostyrene, respectively, at 80 °C reaction temperature. In addition to the characteristic change of regioselectivity, the reversal of absolute configuration as a function of reaction temperature was also observed.
Pd0-mediated rapid coupling of methyl iodide with excess amounts of benzyl- and cinnamylboronic acid esters: Efficient method for incorporation of positron-emitting 11C radionuclide into organic frameworks by coupling between two sp<
Koyama, Hiroko,Zhang, Zhouen,Ijuin, Ryosuke,Siqin,Son, Jeongwan,Hatta, Yuma,Ohta, Masashi,Wakao, Masahiro,Hosoya, Takamitsu,Doi, Hisashi,Suzuki, Masaaki
, p. 9391 - 9401 (2013/07/27)
Pd0-mediated rapid cross coupling between sp3- hybridized carbons of CH3I and benzyl- or cinnamylboronic acid esters using [Pd{P(tert-C4H9)3}2]/CsF in DMF/H2O gave the
Unexpected chemoselective debromination and reduction of 1,1-dibromo-1-alkenes mediated by samarium metal in methanol
Wang, Lei,Li, Pinhua,Xie, Yuanyuan,Ding, Yanbin
, p. 1137 - 1140 (2007/10/03)
An unexpected samarium metal mediated chemoselective debromination and reduction of 1,1-dibromo-1-alkenes in methanol has been developed, which generates vinyl monobromides, alkenes, and alkanes respectively with appropriate molar ratio of samarium to 1,1-dibromo-1-alkene.
