Highly Selective Oxidations of Fe(CO)₃‐Cyclohexadiene Complexes: Synthesis of 4b,8a‐Dihydrocarbazol‐3‐ones and the First Total Synthesis of Carbazomycin A

Abstract

An approach to the synthesis of highly substituted carbazole derivatives such as 2 and 3 is provided by the iron complex 1. Depending on the reaction conditions, this compound undergoes stereoselective cyclization to give either the 4a,9a-dihydro-9H-carbazole 2 or the new, analogously substituted 4b,8a-dihydrocarbazol-3-one. This method allows the total synthesis of carbazomycin A 3. Compound 2 exhibits optical anisotropy, which can be understood in terms of crystal packing.