Radical chemistry of the Breslow intermediate.

by McIntosh, Matt

The co-called Breslow intermediate (1) is implicated in several crit. enzymic transformations, including pyruvate decarboxylase, trans ketolase, and pyruvate oxidase, among others. It is also believed to be an intermediate in a variety of NHC-catalyzed reactions. We have recently reported that Breslow intermediates may undergo homolysis of the N-C bond of the nitrogen substituent at temps. as low as ambient. The principle reaction pathway is radical recombination to provide formal 1,3-rearrangement products. With appropriate substitution, this pathway can be redirected to favor radical disproportionation. We will describe the details of this chem. and provide a mechanistic rationale for the facile C-N homolysis reaction.