Pauson−Khand Reactions of Electron-Deficient Alkenes

Despite the common perception that alkenes possessing electron-withdrawing groups are not adequate substrates for Pauson−Khand (PK) reactions, a number of successful examples of this reaction involving electron-deficient alkenes, such as α,β-unsaturated ketones, esters, nitriles, sulfoxides and sulfones, have been reported in recent years. In the case of the intramolecular PK reaction of 1-sulfinyl-1,6-enynes and 1-sulfonyl-3-oxygenated-1,6-enynes these processes have been applied in asymmetric synthesis. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)