Synthesis of New Chiral 2,2‘-Bipyridine Ligands and Their Application in Copper-Catalyzed Asymmetric Allylic Oxidation and Cyclopropanation
作者:Andrei V. Malkov、Daniele Pernazza、Mark Bell、Marco Bella、Antonio Massa、Filip Teplý、Premji Meghani、Pavel Kočovský
DOI:10.1021/jo034179i
日期:2003.6.1
rate (typicaly 30 min at room temperature) in allylic oxidation of cyclic olefins (52 --> 53). Copper-catalyzed cyclopropanation proceeded with < or =76% enantioselectivity and approximately 3:1 to 99:1 trans/cis-diastereoselectivity (54 --> 55 + 56). The level of the asymmetric induction is discussed in terms of the ligand architecture that controls the stereochemical environment of the coordinated
通过吡啶核的从头构建已经合成了一系列模块化联吡啶型配体1和3-9。这些配体的手性部分来自类异戊二烯手性库,即β-pine烯(10-> 1),3-烯基(14-> 3和5),2-烯基(28-> 4),分别是α-pine烯(43-> 6-8)和醋酸脱氢孕烯醇酮(48-> 9)。由这些配体和(TfO)(2)Cu(1 mol%)衍生的铜(I)配合物在用苯肼原位还原后表现出良好的对映选择性(高达82%ee)和异常高的反应速率(通常30分钟)在室温下)进行环烯烃的烯丙基氧化(52-> 53)。铜催化的环丙烷化的对映选择性<或= 76%,反式/顺式非对映选择性约为3:1至99:1(54-> 55 + 56)。