Mechanistic studies on the iron-promoted deamination reactions of 7-azanorbornadiene derivatives

Abstract

The reaction mechanism for the fragmentation of 7-azanorbornadiene derivatives (ANB; 7-azabicyclo[2.2.1]hepta-2,5-diene) mediated by iron carbonyl compounds was analyzed by substituent effects. The reactions proceed through two stages: a tetracarbonyliron complex (ANB)Fe(CO)₄ forms first followed by a tricarbonyliron complex (ANB)Fe(CO)₃. A linear free energy correlation was found for the decomposition of the latter group of complexes, which implied the existence of a polar transition state. The proposed mechanism was then confirmed by the isolation of new products from certain 2-tosyl ANB complexes in a related reaction.