Research On The Asymmetric Michael Addition Of Azoalkenes With Diazomethylphosphate

Staring from(S)-BINOL, a serial of chiral quaternary ammonium salts based on the phase-transfer catalyst developed by Maruoka were synthesized and used to catalyze the Michael addition of azoalkenes with diazomethylphosphate. The results revealed that: when the binaphthalene beared strong electron-withdrawing group 3,5-bis(trifluoromethyl)phenyl, the right part of the chiral quaternary ammonium salts( call it B) derivates from 3-hydroxypyrrolidine could obtain an excellent results. Further optimizing the reaction condition, 5 mol% loading catalyst, 2.5 equivalent Cs2CO3, and Ph F as solvent under-30 ℃ would be the best condition. The substrate scope was investigated then and we found that most of the results were moderate to good albeit the one with large groups on the aromatic rings of the substrates gave lower yields and ees. We are exploring new catalyst to get better results.