Diastereoselective Reaction of Sulfoxonium Ylides, Aldehydes and Ketenes: An Approach to trans-γ-Lactones

In this paper, a novel approach to γ-lactones from the reaction of sulfoxonium ylides, aldehydes, and ketenes is described. The new ylide-based method provides access to γ-lactones from disubstituted ketenes, in good yields, and with good diastereoselectivity favoring the trans-diastereomer (11 examples with dr ≥ 82:18, dr up to 92:8).