Enhanced anti-Diastereo- and Enantioselectivity in Alcohol-Mediated Carbonyl Crotylation Using an Isolable Single Component Iridium Catalyst
作者:Xin Gao、Ian A. Townsend、Michael J. Krische
DOI:10.1021/jo200068q
日期:2011.4.1
The cyclometalated iridium complex (S)-I derived from [Ir(cod)Cl]2, 4-cyano-3-nitrobenzoic acid, allyl acetate, and (S)-SEGPHOS is conveniently isolated by precipitation or through conventional silica gel flash chromatography. This single-component precatalyst allows alcohol mediated carbonyl crotylations to be performed at significantly lower temperature, resulting in enhanced levels of anti-diastereo-
环金属铱配合物(小号) -我从物[Ir(COD)CL]衍生的2,4-氰基-3-硝基苯甲酸,乙酸烯丙酯,和(小号)-SEGPHOS方便地通过沉淀或通过传统的硅胶快速色谱法分离. 此单组分预催化剂允许醇介导的在显著较低温度下进行羰基crotylations,导致水平提高抗-diastereo-和对映选择性。最重要的是,色谱分离的预催化剂 ( S )- I使羰基巴豆酰化成为可能,这在先前报道的涉及原位生成 ( S )- 的条件下是不可能的我。