view:41248 Last Update: 2024-1-30
Ali Ramazani, Ali Jafari, Ebrahim Ahmadi, Farzin Marandi, Esmail Vessally
Synthesis of Sterically Congested Stabilized Phosphorus Ylides from Acetylenic Esters, 4,4,4-Trifluoro-1-(2naphthyl)-1,3-butanedione, and Triphenylphosphine |
Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione leads to vinyltriphenylphosphonium salts, which undergo Michael addition reaction with conjugate base to produce corresponding sterically congested fluorine-containing phosphorus ylides. Basic alumina powder was found to catalyze conversion of the sterically congested fluorine-containing phosphorus ylides to dialkyl 2-[2-(2-naphthyl)-2-oxoethyl]-3-(1,1,1-triphenyl-λ5-phosphanylidene)succinates in solvent-free conditions under microwave (0.9 KW, 3 min) and thermal (25°C, 120 min.) conditions. |