Thermal decomposition of some 5-substituted 5-azido-5H-dibenzo[a,d]cycloheptenes. A transannular nitrene addition

Abstract

Thermal decomposition of 5-(l-naphthyl)-5-azido-5ff-dibenzo [a,d]cyclohepten.e yields 9-(1 -naphthyl)anthracene, probably via an unstable azasemibulvalene. When the substituent group is smaller than naphthyl, ring contraction is not favored. When the naphthyl ring of the azide has a 4-dimethylamino substituent, the latter is readily replaced by nucleophiles, providing a novel method for the preparation of 9-(4-substituted 1-naphthyl)anthracenes.The preparation of one azasemibulvalene system, 1, has been reported.1 The sandwich structure2 3proposed