Investigations into Intramolecular Cerium‐ and Manganese‐Catalyzed Aerobic Coupling of β‐Oxoesters with Styryl Moieties

Abstract

Bicyclic diketones and lactones are obtained in up to 60% yield in the aerobic, manganese‐catalyzed intramolecular radical cyclization of β‐oxoesters with a six‐membered ring and phenyl or diphenyl allyl substituents in the γ‐position. Intermediate products of this transformation are peroxides, which are processed either reductively with zinc–acetic acid or by Kornblum‐DeLaMare fragmentation (with acetyl chloride–pyridine). The respective congeners with five‐ or seven‐membered rings either undergo only α‐hydroxylation reactions or mixtures of various cyclization products are obtained in low yields. In this study, also cerium‐catalysis was investigated, however, the yields are lower compared to manganese catalysis. The relative configurations of all racemic products were established by X‐ray single crystal structure analyses.