Abstract Addition of catechol to methyl propiolate or ethyl phenylpropiolate in the presence of Ph 3 P leads to methyl 2-(1, 3-benzodioxol-2-yl) acetate or 3-(1-phenylmethylidene)-1, 4- benzodioxin-2-one. 2-Aminophenols react with alkyl propiolates in the presence of Ph 3 P ...