Formation of Disubstituted β-Lactones Using Bifunctional Catalysis

Acid chlorides and aromatic aldehydes react in the presence of a stoichiometric amount of a tertiary amine and catalytic amounts of a
cinchona alkaloid derivative and a Lewis acid to produce β-lactones in high diastereo- and enantioselectivity. The sense of the diastereoselectivity
depends on the substitution of the acid chloride, with the reactions of aliphatic acid chlorides giving predominantly the trans-isomer and
those of alkoxyacetyl chlorides favoring formation of the cis-isomer.