Base catalysed rearrangements involving ylide intermediates. Part 17. The preparation and thermal rearrangement of pentadienylammonioamidates

Abstract

The thermal rearrangements of the (2′E)-penta-2′,4′-dienylammonioamidates (13) give products (14) and (15) that are formally derived from [1,2] and [5,2] rearrangements and, in some cases, the product (16) of a [3,2] rearrangement. The products (14) and (15) are formed by a radical mechanism in which (a) radical recombination to give the products (14) and (15) competes with recombination to give the ammonioamidates (13) and (19) and (b) the translational equilibration of the radical pairs (7) and (8) is fast compared with radical pair recombination and diffusion to give free radicals.