Theoretical study on the mechanism of stable phosphorus ylide in the presence of indole

Phosphorus ylides are reactive systems, which take part in many valuable reactions of organicsynthesis [1,2]. These ylides are most often prepared by the treatment of a phosphonium saltwith a base, and phosphonium salts are usually made from a phosphine and an alkyl halide[3]. Phosphonium salts also are obtained by a Michael addition of phosphorus nucleophiles toactivated olefins, among other methods. The indole moiety and its derivatives are widely usedin making perfumes, agrochemicals, and medicines [4]. In the recent work, the mechanism ofthe reaction between triphenylphosphine 1, dimethyl acetylenedicarboxylate 2 in the presenceof indole as a NH-acid 3 was investigated.