The Intermolecular Pauson-Khand Reaction of meso-Substituted Porphyrins

The intermolecular Pauson-Khand reaction is often limited by the poor reactivity and selectivity of simple alkenes. Here we expanded the range of reagents to simple alkenyl- and alkynyl-substituted porphyrins. The two expected regioisomers could be obtained in a combined yield of up to 72%. In addition, use Of the Pauson-Khand reaction provides a simple and novel pathway for the preparation of porphyrin dimers in a nearly quantitative yield. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)