Electronically controlled asymmetric cyclopropanation catalyzed by a new type of chiral 2,2′-bipyridine
作者:Hei Lam Wong、Yuan Tian、Kin Shing Chan
DOI:10.1016/s0040-4039(00)01306-x
日期:2000.9
An optically active atropisomeric 2,2′-bipyridine was synthesized and its copper complex was used in the asymmetric cyclopropanation of para-substituted styrenes with e.e. values up to 86%; the enantioselectivity exhibited a substrate electronic effect in a linearfreeenergyrelationship.
Strong base and large size cation have been shown to accelerate the rate and the yield of Suzuki coupling of a sterically bulky boronic acid with halopyridines in DME for the synthesis of pyridylphenols.
Enantioselectivity Increases with Reactivity: Electronically Controlled Asymmetric Addition of Diethylzinc to Aromatic Aldehydes Catalyzed by a Chiral Pyridylphenol
作者:Huichang Zhang、Feng Xue、T. C. W. Mak、Kin Shing Chan
DOI:10.1021/jo9609889
日期:1996.11.15
Base effect on the cross-coupling of bulky arylboronic acid with halopyridines
作者:Huichang Zhang、Kin Shing Chan
DOI:10.1016/0040-4039(95)02343-7
日期:1996.2
Base has been shown to have a remarkable effect on acceleration of the rate of Suzuki coupling of sterically bulky boronic acid with halopyridines in non-aqueous solvent.