Asymmetric Synthesis of β-Lactams through Copper-Catalyzed Alkyne-Nitrone Coupling with a Prolinol-Phosphine Chiral Ligand
作者:Yurie Takayama、Takaoki Ishii、Hirohisa Ohmiya、Tomohiro Iwai、Martin C. Schwarzer、Seiji Mori、Tohru Taniguchi、Kenji Monde、Masaya Sawamura
DOI:10.1002/chem.201702070
日期:2017.6.22
Prolinol–phosphine chiral ligands enabled highly enantioselective copper‐catalyzed intermolecular alkyne–nitrone coupling (Kinugasa reaction) to produce 1,3,4‐trisubstituted chiral β‐lactams. A high level of enantiocontrol was achieved not only with aryl‐ or alkenylacetylenes but also with alkylacetylenes, which were important but unfavorable substrates in the previously reported protocols. Two‐point
脯氨醇-膦的手性配体使得高度对映选择性的铜催化的分子间炔-硝基偶联(Kinugasa反应)产生了1,3,4-三取代的手性β-内酰胺。不仅使用芳基或烯基乙炔,而且使用烷基乙炔都可以实现高水平的对映体控制,这在先前报道的方案中是重要的但不利的底物。提出了由OH-H···O和C(sp 3)-H··· O的氢键构成的手性配体与氮氧阴离子的两点氢键。