Silyl substituted furans in the stereoselective Birch reduction

Chiral derivatives of 3-silyl-2-furoic acid were prepared and subjected to a Birch reductive alkylation reaction. It was found that the presence of a silicon atom, ortho to the chiral auxiliary, enabled the synthesis of dihyd rofurans with high levels of stereo selectivity. We believe that the silico n group is essential in order to control the geometry of the enolate formed in the reduction regime. Remarkably, the partial reduction conditions coul d be tailored so that the silicon is removed in situ, before the furan deri ved enolate is alkylated. (C) 2001 Elsevier Science Ltd. All rights reserve d.