protonation of the highly reactive 1:l intermediate produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by 2- hydroxyacetophenone leads to vinyltriphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with the conjugate base to produce compounds 4,5, and 6 in 1 : 1.2:0.5 ratios

Protonation of the highly reactive 1:l intermediate produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by 2- hydroxyacetophenone leads to vinyltriphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with the conjugate base to produce compounds 4,5, and 6 in 1 : 1.2:0.5 ratios