Synthesis of Highly Functionalized <i>γ</i>‐Lactones <i>via</i> 1,5‐Electrocyclic Ring Closure

Abstract

Abstract We have investigated 1,5‐electrocyclic ring‐closure reactions of conjugated esters with dimethyl diazomalonate in the presence of [Cu(acac) 2 ] as catalyst. Our new protocol offers an easy entry to various polyfunctionalized γ ‐lactones in high yields. Their subsequent derivatives may be used as valuable intermediates, especially in the synthesis of natural products and their analogues.