Highly Enantioselective Addition of In Situ Prepared Arylzinc to Aldehydes Catalyzed by a Series of Atropisomeric Binaphthyl-Derived Amino Alcohols
作者:Gui Lu、Fuk Yee Kwong、Ji-Wu Ruan、Yue-Ming Li、Albert S. C. Chan
DOI:10.1002/chem.200501048
日期:2006.5.15
catalyst, both enantiomers of many pharmaceutically interesting diarylmethanols can be obtained by the proper combination of various arylzinc reagents with different aldehydes; this catalytic system also works well for the phenylation of aliphatic aldehydes to give up to 96 % ee.
The enantioselectiveaddition of organozincreagents to aromatic and aliphatic aldehydes 1 gives secondary alcohols 2 with excellent enantioselectivities in high yields through the catalytic use of (R)-3,3′-bis(diphenylphosphinoyl)-BINOL (3) or (R)-3,3′-bis(diphenylthiophosphinoyl)-BINOL (4) without Ti(IV) complexes. The coordination of the O or S atom of a (thio)phosphinoyl group bearing a BINOL backbone
Application of β-Hydroxysulfoximines in Catalytic Asymmetric Phenyl Transfer Reactions for the Synthesis of Diarylmethanols
作者:Jörg Sedelmeier、Carsten Bolm
DOI:10.1021/jo7016718
日期:2007.11.1
Enantiomerically enriched diarylmethanols have been prepared by catalyzed asymmetric phenyl transfer reactions onto aromatic aldehydes with use of readily available β-hydroxysulfoximines as catalysts. As the aryl source, combinations of diethylzinc with either diphenylzinc or triphenylborane have been applied affording arylphenylmethanols with up to 93% ee in good yields. Various functionalized aldehydes
The preparation of new chiral amino alcohols that possess a flexible biphenylazepine moiety and can work as tropos catalysts, is presented. In these compounds, the sign of the induced axial chirality depends on the nature of stereogenic centers near the flexible fragment and can determine the stereochemical outcome in asymmetric reactionsmediated by them. The efficiency of these new ligands has been
the resulting mixed titanium reagents undergo addition to aldehydes with high enantioselectivities (typically >90% ee) and high yields. The method is applicable to various combination of aldehydes (R 1 CHO; R 1 = aryl, heteroaryl, 1-alkenyl, and alkyl) and Grignard reagents (R 2 MgX; R 2 = primary alkyl and aryl). Thus, a variety of enantiomerically enriched secondary alcohols (R 1 CH*(OH)R 2 ) can