Iridium-Catalyzed Allylation Of Morita-Baylis-Hillman Acetates With Indolinone Compounds

A new iridium-catalyzed allyllic alkylation of Morita-Baylis-Hillman (MBH) acetates with 3-(substituted phenyl)-2-oxindole derivatives was explored. It was found that the regioselection catalyzed by iridium was significantly different from that catalyzed by palladium. A class of 3, 3'-disubstituted-2-oxindoles with new structures were synthesized directly and efficiently. By screening the ligands such as phosphoramidites, bisphosphine and monophosphines, metal sources, solvents, bases and reaction temperature, the optimized catalytic system and conditions for the reaction were obtained: [Ir(COD)Cl](2)(molar fraction of 5%) and phosphoramidite ligand L6(molar fraction of 10%) as the catalyst, CH3CN as the solvent, Cs2CO3 as the base, and reaction temperature of -30 degrees C, reaction time of 25 h. Under the optimized conditions, the substrates with different types of substituents were investigated. It was found that the substrates had good universality. The lowest yield of the products reached 84%, and the best one was 98%. The electronic effect of substituents was not obvious on the yield. Some other types of bisphosphine and monophosphine ligands along with iridium also had good catalytic performance.