Synthetic approaches to α,β-unsaturated δ-lactones and lactols

The synthesis of six-membered unsaturated delta-lactones has generated considerable interest, due to their occurrence in a large number of natural products possessing potent biological activities. This microreview attempts to illustrate the different strategies used to obtain such compounds, with a special emphasis on catalytic and asymmetric approaches. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).