Intramolecular Carbenoid Insertions: the Reactions of α-Diazoketones Derived from Pyrrolyl and Indolyl Carboxylic Acids with Rhodium(II) Acetate

α-Diazoketones derived from pyrrolyl- and indolyl-carboxylic acids were prepared and their Rh2(OAc)4 catalyzed decomposition chemistry was studied. These reactions generally resulted in the alkylation of the heteroaromatic system by the ketocarbenoid and in some instances the systems underwent CH or NH insertions. Evidence that some of these reactions proceed via a cyclopropane intermediate is presented. The methodology described provides facile access to fused pyrrolyl– or indolyl–cycloalkanone systems wherein the carbonyl is beta to the heteroaromatic system.