新型双膦配体及钯催化的烯丙基烷基化反应用于构筑季碳手性中心

Synthesis of Novel Diphosphine Ligands and Their Applications in Palladium- Catalyzed Allylic Alkylation to Construct Chiral Quaternary Carbon Center

从二茂铁唑啉膦化合物(Sp)-1出发,合成了一类平面手性二茂铁修饰的口袋型双膦配体(R,R,Sp.Sp)-4和(S,S,Sp,Sp)-4.这类配体在前手性亲核试剂的不对称烯丙基化构筑手性季碳中心的反应中,显示了较好的反应活性及对映选择性.当利用亚胺的氨基酸酯衍生物时,可以得到一些非天然的季碳氨基酸衍生物,ee值最高可以达到75.3%一些简单的酮的烯醇负离子也可用作亲核试剂,产物为α-位双取代的具有季碳中心的酮,ee值可高达95%.

Planar chiral ferrocene modified pocket ligands (R, R-,R- S-p, S-p) - 4 and ( S, S, S-p, S-p) - 4 were synthesized from (S-p) - 1. The ligands were found to be effective in palladium - catalyzed asymmetric allylic alkylation to construct chiral quaternary carbon center. The products up to 75.3% ee by using iminoesters as a carbon nucleophile and up to 95% ee by using the simple ketone enolates as a carbon nucleophile were afforded, respectively.