Preparation and Resolution of a Modular Class of Axially Chiral Quinazoline-Containing Ligands and Their Application in Asymmetric Rhodium-Catalyzed Olefin Hydroboration
作者:David J. Connolly、Patrick M. Lacey、Mary McCarthy、Cormac P. Saunders、Anne-Marie Carroll、Richard Goddard、Patrick J. Guiry
DOI:10.1021/jo049195+
日期:2004.10.1
Displacement of the resolving agent by reaction with 1,2-bis(diphenylphosphino)ethane afforded enantiopure ligand in each case. Their rhodium complexes were prepared and applied in the enantioselective hydroboration of a range of vinylarenes. The quinazolinap catalysts were found to be extremely active, giving excellent conversions, good to complete regioselectivities, and the highest enantioselectivities obtained
描述了一系列轴向手性含喹唑啉配体的制备和拆分,其中关键步骤是金属催化的萘基-磷键形成,萘-喹唑啉Suzuki偶联以及从相应的步骤制备Suzuki亲电子组分亚氨酸酯和邻氨基苯甲酸。由外消旋次膦胺和(+)-二-μ-氯代双[(R)-二甲基(1-(1-萘基)乙基)氨基-C 2衍生的非对映体palladacycles。,N]二钯(II)通过分步结晶分离。通过X射线晶体学分析确定所得非对映异构体的构型。在每种情况下,通过与1,2-双(二苯基膦基)乙烷反应置换拆分剂得到对映体纯配体。制备了它们的铑配合物,并将其用于一系列乙烯基芳烃的对映选择性硼氢化。所述quinazolinap催化剂被发现是非常活跃,赋予优异的转化率,良好的到完全区域选择性,和迄今为止获得最高的对映选择性为乙烯基芳烃类的几个成员,包括顺式-β -甲基苯乙烯(97%),顺式-芪(99 %)和茚(99.5%)。