Convenient approach to polyoxygenated dibenzo[c,e]pyrrolo[1,2-a]azepines from donor-acceptor cyclopropanes

A short convenient approach to polyoxygenated tetrahydrodibenzo[c,e]pyrrolo[1,2-a]azepines from the donor-acceptor cyclopropanes was developed. A simple synthetic sequence involves: (a) cyclopropane ring opening with azide ion and Krapcho dealkoxycarbonylation; (b) azide-to-imine transformation followed by imine reduction; (c) the oxidative cyclization of 5-aryl-1-benzylpyrrolidin-2-ones, the key intermediates for this approach.