K. Iseki, Y. Kuroki, Daisuke Asada
Jul 28, 1997
Citations
0
Influential Citations
47
Citations
Journal
Tetrahedron
Abstract
Abstract Aldol reaction of aldehydes with difluoroketene ethyl trimethylsilyl acetal (1) in the presence of a substoichiometric amount of chiral Lewis acid 2 or 3 provides the corresponding α,α-difluoro β-hydroxy esters 4–12 with high enantioselectivities (up to 98% ee). Reaction temperature has a great influence on the enantiofacial selection of aldehydes; the reactions of benzyloxyacetaldehyde catalyzed by Lewis acid 2 at −78 and −30°C gave the (+)- and (−)-α,α-difluoro β-hydroxy esters 7 in optical yields of 98% and 85%, respectively.