Pentanidium-Catalyzed Enantioselective Phase-Transfer Conjugate Addition Reactions

A new chiral entity, pentanidium, has been shown to be an excellent chiral phase-transfer catalyst. The enantioselective Michael addition reactions of tert-butyl glycinate−benzophenone Schiff base with various α,β-unsaturated acceptors provide adducts with high enantioselectivities. A successful gram-scale experiment at a low catalyst loading of 0.05 mol % indicates the potential for practical applications of this methodology. Phosphoglycine ester analogues can also be utilized as the Michael donor, affording enantioenriched α-aminophosphonic acid derivatives and phosphonic analogues of (S)-proline.

研究表明，新型手性实体pentanidium是一类性能优异的手性相转移催化剂。甘氨酸叔丁酯-二苯甲酮希夫碱与多种α,β-不饱和受体的对映选择性迈克尔加成反应，可得到具有高对映选择性的加合产物。在0.05 mol%的低催化剂负载量下开展的克级规模实验取得成功，证实该方法具备实际应用潜力。磷酰甘氨酸酯类似物亦可作为迈克尔给体参与反应，能够获得对映富集的α-氨基膦酸衍生物以及(S)-脯氨酸的膦酸类似物。