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).