The Reaction of Diazocyclopentadienyl Compounds with Cyclomanganated Arenes as a Route to Ligand‐Appended Cymantrenes

Abstract

Abstract The thermolysis of various cyclomanganated arenes in the presence of 5‐diazocyclopentadiene, 7‐diazoindene or 9‐diazofluorene afforded the corresponding arenes tethered with cymantrenyl, benzocymantrenyl or dibenzocymantrenyl groups in fair to good yields. This reaction implies a multi‐facetted mechanism that consists of three steps: the insertion of an alkylidene moiety into a C−Mn bond, a C Ar −C bond formation and several haptotropic ring‐slippages. The coupling reaction has proven to be particularly efficient with Mn(CO) 4 chelates derived from acetylarenes and nitrogen‐containing heterocycles. In one case of a 2‐phenyl‐2‐oxazoline complex, the coupling with 9‐diazofluorene yields a new η 1 ‐dibenzocymantrene complex in which the Mn(CO) 4 moiety is chelated and is part of a six‐membered metallacycle. The results of this study are mainly supported by the molecular structures of nine new complexes obtained by X‐ray diffraction analyses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)