作者:Carl A. Busacca、Danja Grossbach、Regina C. So、Erin M. O'Brie、Earl M. Spinelli
DOI:10.1021/ol0340179
日期:2003.2.1
new BIPI ligands are phosphinoimidazolines that can be electronically tuned in three different ligand regions to explore electronic effects in asymmetric catalysis. Their application to the asymmetric Heck reaction (AHR) in the creation of a chiral quaternary center is described. Enantioselectivity is shown for the first time to depend linearly on phosphine electron density. Changing the ligand basicity
[结构:见正文]新的BIPI配体是膦基咪唑啉,可在三个不同的配体区域进行电子调节,以探索不对称催化中的电子效应。描述了它们在手性四元中心生成中的不对称Heck反应(AHR)中的应用。首次显示出对映选择性线性依赖于膦电子密度。通过改变R(2)或R(3)取代基来改变配体碱性,会逆转面部选择性。