Preparation of Novel N-Vinyl-, N-(1-Butylvinyl)-, and N-(1-Methyl-1-pentenyl)iminotriphenylphosphoranes and Their Reactions with α,β-Unsaturated Ketones

The novel N-vinyl-(2a) and a mixture of N-(1-butylvinyl)-(2b) and N-(1-methyl-1-pentenyl) iminotriphenylphosphoranes (2c) were prepared by the reaction of azidoethylene and 2-azido-1-hexene with triphenylphosphine, respectively. The thermal reaction of 2a, 2b, and 2c with α,β-unsaturated ketones undergoes an enamine-type alkylation and the subsequent aza-Wittig reaction to give pyridine derivatives in modest yields.