Diastereoselective Synthesis of γ-Lactones by the Aldol-Type Reaction of Ethyl 2,2-Dialkoxycyclopropanecarboxylates with Aldehydes

Abstract Ethyl 2,2-dialkoxycyclopropanecarboxylates, considered as three carbon 1,3-dipole equivalents, reacted smoothly with aldehydes in the presence of titanium(IV) bromide to give γ-lactones in good yields with high diastereoselectivity.