The title compounds were prepared in high yield by protonation of the reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylate by phthalimide, followed by nucleophilic addition of the imidic nitrogen anion to the vinyl phosphonium salts. A dynamic NMR study was also performed.
One-Pot Synthesis of 2-Substituted Indoles from 2-Aminobenzyl Phosphonium Salts. A Formal Total Synthesis of Arcyriacyanin A