An unusually strict product partition of an excited diazirine–carbene system

Abstract
Photolysis of 3-tert-butyl-3-chlorodiazirine produces 2-chloro-3-methyl-but-2-ene and 2,2-dimethyl-1-chlorocyclopropane; the former stems from 1,2-methyl migration and nitrogen loss in the excited state diazirine, whilst the latter is a product of 1,3-CH insertion in the tert-butylchlorocarbene derived from the diazirine.