Base catalysed rearrangements involving ylide intermediates. Part 12. The preparation and reactions of 2-oxidoanilinium ylides

Abstract

2-Oxidoanilinium ylides (22) may be prepared from the corresponding quaternary salts (21) by reaction with aqueous sodium hydroxide. The ylides (22) rearrange on heating to give the products (23) of [1,4] rearrangements which, on the basis of mixing experiments, are intramolecular processes. The N-allyl ylide (22c) rearranges to give both the ether (23c) and the allylphenol (30); a study of the rearrangements of specifically deuteriated ylides (41) shows that these reactions involve competing concerted and radical pair processes. The observation of CIDNP during the formation of the allylphenol (30) is shown to be associated with the minor radical pair pathway for the formation of this product.