In situ alcohol oxidation-Wittig reactions using N-methoxy-N-methyl-2-(triphenylphosphoranylidine)acetamide: application to the synthesis of a novel analogue of 5-oxo-eicosatetraenoic acid

Benzylic, allylic, propargylic and unactivated alcohols can be oxidised with activated manganese dioxide in the presence of N-methoxy-N-methyl-2-(triphenylphosphoranylidine)acetamide to generate directly the corresponding α,β-unsaturated Weinreb amides. Elaboration of the resulting Weinreb amides is also described, in particular as part of a new route to analogues of the arachidonic acid metabolite 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid.