Substrate and Catalyst Screening in Platinum-Catalyzed Asymmetric Alkylation of Bis(secondary) Phosphines. Synthesis of an Enantiomerically Pure <i>C</i><sub>2</sub>-Symmetric Diphosphine
作者:Brian J. Anderson、David S. Glueck、Antonio G. DiPasquale、Arnold L. Rheingold
DOI:10.1021/om800534k
日期:2008.10.13
Platinum-catalyzed asymmetric alkylation of bis(secondary) phosphines was investigated. The modular design of the catalyst precursor Pt(diphos*)(R′)(Cl) and the substrates, a bis(secondary) phosphine HRP∼PHR and a benzyl halide, along with an efficient 31P NMR screening method, enabled rapid evaluation of the rate and diastereoselectivity of these reactions. These experiments identified a selective
研究了铂催化的双(仲)膦的不对称烷基化反应。催化剂前体Pt(diphos *)(R')(Cl)和底物,双(仲)膦HRP〜PHR和苄基卤的模块化设计以及有效的31 P NMR筛选方法可实现快速评估这些反应的速率和非对映选择性。这些实验确定了选择性催化剂Pt(DuPhos)(Ph)(Cl),并且表明PhHP(CH 2)3 PHPh(2)的烷基化比PhHP(CH 2)2 PHPh(1),MesHP(CH 2)3 PHMes(3)或1,1'-(C5 H 4 PHPh)2 Fe(4)。的烷基化1与ö -CF 3 Ç 6 ħ 4 CH 2溴采用基NaOSiMe 3和催化剂前体的Pt(([R ,- [R )-我-Pr-DUPHOS)(PH)(CL),或类似的ME- DuPhos络合物,得到二膦Ph(CH 2 o -CF 3 C 6 H 4)P(CH 2)2 P(CH 2 o -CF 3 C 6 H4)P