Synthesis of penicillanate dimers: an X-ray crystal structure of a penicillanylidene-penicillanate

Abstract

On treatment with copper bis(acetoacetonate) in dichloromethane, 2,2,2-trichloroethyl 6-diazopenicillanate (1), and its (1S)-S-oxide and S,S-dioxide (2) and (3), were found to lose nitrogen and dimerize to give mixtures of (E)- and (Z)- alkenes (5)–(10), in which the (E)-isomers (5)–(7) predominated. The structure of the minor dimer from the 6-diazopenicillanate (1) was established as (8) by X-ray crystallography.