A WITTIG REACTION ON MUCOCHLORIC AND MUCOBROMIC ACIDS. PREPARATION OF ETHYL(2E,4Z)-4,5-DIHALO-2,4-PENTADIENOATES AND ALKYL (2E)-5-BROMO-2-PENTEN-4-YNOATES

Article abstract of DOI:10.1016/S0040-4039(00)85822-0

Reaction of mucochloric and mucobromic acid with (ethoxycarbonylmethylene)triphenylphosphorane affords the ethyl ester of (2E,4Z)-4,5-dichloro- and (2E,4Z)-4,5-dibromo-2,4-pentadienoic acid respectively; in the latter case ethyl (2E)-5-bromo-2-penten-4-ynoate is formed concomittantly.