Diastereodivergent Aldol Reactions of β-Alkoxy Ethyl Ketones: Modular Access to (1,4)-<i>syn</i>and -<i>anti</i>Polypropionates

Abstract

Asymmetric substrate-controlled aldol reactions of ethyl ketones of type 4 with aldehyde 3 are reported. Modular access to all possible syn- and anti-aldol products was obtained by careful choice of reaction conditions. To achieve good selectivities in this diastereodivergent approach, selection of the protective group on the β-oxygen of the enolate (R2) was of critical importance.