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7757098 
Journal Article 
Diastereoselectivity in the Lewis acid mediated aldol reaction of chiral alpha, beta-epoxyaldehydes with a ketene silyl acetal 
Fontaine, E; Baltas, M; Escudier, JM; Gorrichon, L 
1996 
1 
Monatshefte für Chemie / Chemical Monthly
ISSN: 0026-9247
EISSN: 1434-4475 
Springer Wien 
127 
5 
519-528 
English 
WOS:A1996UM73800008 
The Lewis acid mediated aldol reaction of chiral α, β-cis and trans epoxyaldehydes 1 and 2 with tert-butyl ketene silyl acetal proceeds mainly with anti diastereofacial preference. The best results were obtained for cis epoxyaldehyde 1 in the presence of catalytic amounts of BiCl3 · 1.5 eq. ZnI2 (anti:syn ∼ 13:1), whereas the poorest stereoselectivity was observed when an excess of LiClO4 was used (anti:syn ∼ 1:1). The more stable epoxyaldehyde conformers were determined and the diastereofacial preference was found to be in agreement with a nucleophilic attack on the energetically more favoured conformers. 
diastereoselection; epoxyaldehydes; enolate, optically active gamma, delta-epoxy-beta-hydroxyesters