A route to 3H-1,2-diazepines by the 1,7-electrocyclisation of α,βγ,δ-unsaturated diazo-compounds

Abstract

In the thermal cyclisation of α,β;γ,δ-unsaturated diazo-compounds the type (6) with a cis hydrogen atom at the terminal carbon atom undergo 1,7 ring closure to give 3H-1,2-diazepines while those (9) with a methyl group at that position take an alternative reaction path to give pyrazoles via 1,5 cyclisation.