Reversal of stereoselectivity in the Evans aldol reaction of α,α-difluoro and α,α,α-trifluoro carbonyl compounds

Article abstract of DOI:10.1016/0040-4020(95)00858-6

The Evans aldol reaction of hexafluoroacetone and trifluoroacetaldehyde causes complete reversal of diastereofacial selectivity. The boron enolate derived from N-acyloxazolidinone 2 reacts with trifluoroacetaldehyde to give anti and "non-Evans" syn aldols