Diastereoselective Synthesis of γ-Butyro-lactones

Significance

Reported here is the diastereoselective synthesis of polysubstituted γ-butyrolactones, containing three stereocenters, by the sequential reaction of Reformatsky reagents with silyl glyoxylate and ketones. Among enolates, the use of zinc enolates under standard conditions proved to be the most efficient for this transformation. After aldol addition of a Reformatsky reagent to a silyl glyoxylate, a [1,2]-Brook rearrangement ensues to form a new enolate which undergoes a second aldol reaction with a ketone to give the product.