Synthesis of dialkyl 2-(2-oxo-2-phenylethyl)-3-(1,1,1-triphenyl-lambda(5)-phosphanylidene)suc cinates from triphenylphosphine, acetylenic ester and 4,4,4-trifluoro-1-phenyl-1,3-butanedione in the presence of basic alumina powder

摘要

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 4,4,4-trilfluoro-1-phenyl-1,3-butanedione leads to vinyltriphenylphosphonium salts, which undergo Michael addition reaction with conjugate base to produce corresponding phosphorus ylides. Basic alumina powder was found to catalyze conversion of the phosphorus ylides to dialkyl 2-(2-oxo-2-phenylethyl)-3-(1,1,1-triphenyl-lambda(5-)phosphanylidene)suc cinates in solvent-free conditions under microwave (0.9 KW, 3 min) and thermal (25 degrees C, 120 min) conditions.