Synthesis of substituted α,β-unsaturated δ-lactones from vinyl tellurides

A new approach for the synthesis of α,β-unsaturated δ-lactones, a unit present in many natural products with interesting biological activities is described. The approach was based on the use of a vinyl telluride, and it is complementary to the methods using ring-closing metathesis. The sequence was performed in good overall yield with retention of the Z-double bond geometry.