PHOTOLYSIS OF N,N-DIETHYLDIAZOACETAMIDE - PARTICIPATION OF A NON-CARBENIC PROCESS IN INTRA-MOLECULAR CARBON-HYDROGEN INSERTION

The mechanistic details of the photochemical process of N, N-diethyldiazoacetamide (1) have been investigated in order to elucidate the relation of intramolecular C-H insertion selectivity with the reacting state. The examination of the effects of sensitizer and quenchers on the product distributions showed that singlet carbene is involved in the formation of γ-lactam whereas the singlet excited state of 1 is the most likely intermediate leading to the β-lactam. The nearly equal participation of the carbene and rearrangement processes in the excited state is in marked contrast with the result of diazoacetone and is interpreted in terms of the influence of the equilibrium ratio of the Z and E forms of 1. The reaction patterns of each reacting state are suggested to be affected by a conformational effect, i.e., the closest approach distance to the carbene center, for the carbene process, and an electronic one, i.e., stabilization in the transition state, for the excited 1 reaction. © 1979, American Chemical Society. All rights reserved. © 1979, American Chemical Society. All rights reserved.