Chiral NCN Pincer Rhodium(III) Complexes with Bis(imidazolinyl)phenyl Ligands: Synthesis and Enantioselective Catalytic Alkynylation of Trifluoropyruvates with Terminal Alkynes
作者:Tao Wang、Jun-Long Niu、Shuang-Liang Liu、Juan-Juan Huang、Jun-Fang Gong、Mao-Ping Song
DOI:10.1002/adsc.201200967
日期:2013.3.25
NCN pincer rhodium(III) complexes with bis(imidazolinyl)phenyl ligands have been conveniently synthesized from easily available materials. The complexes were subsequently applied in the enantioselective addition of terminal alkynes to trifluoropyruvates. With catalyst loading of 1.5–3.0 mol%, the alkynylation of ethyl or methyl trifluoropyruvate with a variety of electronically and structurally diverse
方便地从容易获得的材料中合成了一系列具有双(咪唑啉基)苯基配体的新型手性C 2对称NCN钳型铑(III)配合物。随后将络合物用于将末端炔对映体选择性地添加到三氟丙酮酸中。在催化剂负载量为1.5–3.0 mol%的情况下,三氟丙酮酸乙酯或三氟丙酮酸与各种电子和结构上不同的末端炔烃进行炔基化反应,得到旋光性三氟甲基取代的叔炔丙醇,对映体选择性高达ee > 99%,且收率高。尽管对映选择性很好(85-98%ee)仅在最佳条件下对某些脂族末端炔烃才能实现,对于芳族以及杂芳族炔烃和烯炔而言,对映选择性始终优异(94%至> 99%ee)。