a broad substrate scope and good functional group tolerance and allows the rapid assembly of various valuable axially chiral biaryls in good to high yields (up to 92% yield) with high to excellent enantioselectivities (up to 96% ee). Moreover, this report represents a rare example that a carbonyl group of esters is reduced under homogeneous asymmetric CuH catalysis.
Catalytic <i>atropo</i>-Enantioselective Reduction of Biaryl Lactones to Axially Chiral Biaryl Compounds
作者:Tomoko Ashizawa、Saiko Tanaka、Tohru Yamada
DOI:10.1021/ol800802c
日期:2008.6.1
The atropo-enantioselective borohydride reduction with dynamic kinetic resolution of biaryl lactones was catalyzed by an optically active beta-ketoiminatocobalt(II) complex to afford optically active biaryl compounds. Chiral HPLC analysis of the starting biaryl lactones was performed at various temperatures to determine suitable reaction conditions for dynamic kinetic resolution. Various types of axially
Catalytic<i>atropo</i>-Enantioselective Preparation of Axially Chiral Biaryl Compounds
作者:Tomoko Ashizawa、Tohru Yamada
DOI:10.1246/cl.2009.246
日期:2009.3.5
The atropo-enantioselective ring-opening of biaryl lactones with methanol was catalyzed by an optically active AgBF4–phosphine complex to afford axially chiral biaryl compounds. The addition of triisobutylamine provided a dramatic rate acceleration in the reaction. Various types of axially chiral biaryl compounds were obtained with high enantioselectivity.