π‑Coordinating Chiral Primary Amine/Palladium Synergistic Catalysis for Asymmetric Allylic Alkylation

We report an arene-containing chiral primary amine as a dual aminocatalyst and ligand: the π-coordinating aminocatalyst/palladium synergistic catalysis for asymmetric allylic alkylation of α-branched β-ketocarbonyls. The use of arene-containing chiral primary amine catalyst led to not only enhanced reaction rate but also reversed chiral induction compared with its sterically bulky derivative. Both enantiomers of the allylic adducts bearing acyclic all-carbon quaternary stereocenters could be obtained from the same configured chiral aminocatalysts with high efficiency and excellent regio-, stereo-, and enantioselectivity. Mechanistic studies revealed a distinctive Pd-arene π-coordination mode for effective catalysis. The π-coordinating chiral primary amine catalyst could be successfully applied in the asymmetric allylation reactions of vinylethylene carbonates, vinyl epoxides, or simple allylic alcohols.

我们报道了一款兼具氨基催化剂与配体双功能的含芳烃手性伯胺：该π配位型氨基催化剂可与钯协同催化α支化β酮羰基化合物的不对称烯丙基烷基化反应。与空间位阻较大的衍生物相比，使用该含芳烃手性伯胺催化剂不仅可提升反应速率，还能逆转手性诱导方向。仅使用同一构型的手性氨基催化剂，即可高效制备带有非环全碳季碳立体中心的烯丙基加成产物的两种对映异构体，且产物具有优异的区域选择性、立体选择性及对映选择性。机理研究表明，该催化体系通过独特的钯-芳烃π配位模式实现高效催化。这款π配位型手性伯胺催化剂还可成功应用于乙烯碳酸酯、乙烯基环氧化物及简单烯丙醇的不对称烯丙基化反应中。