Alkenylphosphonates: unexpected products from reactions of methyl 2-[(diethoxyphosphoryl)methyl]benzoate under Horner-Wadsworth-Emmons conditions.
Methyl 2-[(diethoxyphosphoryl)methyl]benzoate reacts with several aldehydes to produce an alkenylphosphonate as the major product, together with varying amounts of the expected Horner-Wadsworth-Emmons product, a 1,2-disubstituted E-alkene. Use of a bulky aldehyde or the tert-butyl ester favours the normal HWE product.