Chiral Magnesium BINOL Phosphate-Catalyzed Phosphination of Imines: Access to Enantioenriched α-Amino Phosphine Oxides

A new method to synthesize chiral α-amino phosphine oxides is reported. The reaction combines N-substituted imines and diphenylphosphine oxide and is catalyzed by a chiral magnesium phosphate salt. A wide variety of aliphatic and aromatic aldimines substituted by electron-neutral benzhydryl or dibenzocycloheptene groups were excellent substrates for the addition reaction. The dibenzocycloheptene protected imines afforded improved enantioselectivity in the resulting products. Substituted diphenylphosphine oxide nucleophiles also showed good reactivity.

本研究报道了一种合成手性α-氨基氧化膦（chiral α-amino phosphine oxides）的全新方法。该反应以N-取代亚胺与二苯基氧化膦（diphenylphosphine oxide）为底物，以手性磷酸镁盐（chiral magnesium phosphate salt）作为催化剂。多种带有电子中性二苯甲基（benzhydryl）或二苯并环庚烯（dibenzocycloheptene）取代基的脂肪族与芳香族醛亚胺（aldimines），均可作为该加成反应的优良底物。经二苯并环庚烯保护的亚胺，可使产物获得更优异的对映选择性（enantioselectivity）。带有取代基的二苯基氧化膦亲核试剂同样表现出良好的反应活性。