Novel quasiphosphonium ylides from the reaction of trialkyl phosphites with dialkyl benzoylphosphonates: evidence for carbene intermediates in the intramolecular cyclisation of 2-substituted dialkyl benzoylphosphonates

Abstract

The reaction of dialkyl aroylphosphonates 1 with trialkyl phosphites leads to the formation of novel quasi-phosphonium ylides 4 which in some cases thermally rearrange to the bisphosphonates5. 2-Substituted dialkyl aroylphosphonates may also undergo intramolecular cyclisation under these conditions. Evidence is presented for the involvement of the carbene intermediates 3.