Stereoselectivity of the Honda-Reformatsky reaction in reactions with ethyl bromodifluoroacetate with α-oxygenated sulfinylimines.

The Reformatsky reaction of ethyl bromodifluoroacetate to α-oxygenated sulfinylimines is described. Using Honda-Reformatsky conditions, the reaction proceeds with double diastereodifferentiation, with the configuration of the sulfinyl group determining the stereochemical course of the reaction. Excellent diastereoselectivities (>94:6) are obtained for the matched cases. In contrast, reaction with sulfinylimines derived from unsubstituted alkanals proceeded with virtually no diastereoselectivity.