Bifunctionalized Allenes. Part XXIII. An Efficient Method for Regioselective Synthesis of 5-Phosphorylated Allenecarboxylates

An efficient method for regioselective synthesis of 5-(dimethoxyphosphoryl)-allenecarboxylates by an atom economical [2,3]-sigmatropic rearrangement of the mediated 3-(dimethoxyphosphanyloxy)-alk-4-ynoates is described. Alkyl 5-(dimethoxyphosphoryl)-alka-3,4-dienoates can be readily prepared via reaction of alkyl 3-hydroxy-alk-4-ynoates with dimethylchlorophosphite in the presence of a base. Alkyl 3-hydroxy-alk-4-ynoates were prepared by reaction of the metallated acetylenes with commercialy available alkyl 3-oxoalkanoates.