SummaryA copper-catalyzed cascade reaction of α,β-unsaturated esters with keto esters is reported. It features a copper-catalyzed reductive aldolization followed by a lactonization. This method provides a facile approach to prepare γ-carboxymethyl-γ-lactones and δ-carboxymethyl-δ-lactones under mild reaction conditions.

Copper-Catalyzed Cascade Reactions of ,-Unsaturated Esters with Keto Esters. -The reaction proceeds through conjugate addition of copper hydride, generated in situ, to ,-unsaturated esters, followed by the aldolization with a keto ester and lactonization. -(LI*, Z.; WANG, C.; LI, Z.; Beilstein J. Org. Chem. 11 (2015) 213-218, http://dx.doi.org/10.3762/bjoc.11.23 ; Coll. Environ. Chem. Eng., Dalian Univ., Dalian 116622, Peop. Rep. China; Eng.) -G. Mueller 22-056