Rhodium(II)-Catalyzed Asymmetric Cyclopropanation and Desymmetrization of [2.2]Paracyclophanes
作者:Duc Ly、John Bacsa、Huw M. L. Davies
DOI:10.1021/acscatal.4c01292
日期:——
2]paracyclophane derivatives are of considerable interest because of their potential in asymmetric catalysis and the development of chiral materials. This study describes the scope of rhodium-catalyzed reactions of aryldiazoacetates with [2.2]paracyclophanes. The reaction with the parent [2.2]paracyclophane resulted in cyclopropanation at two positions, the ratio of which is catalyst-controlled. Because of the
手性[2.2]对环芳烷衍生物因其在不对称催化和手性材料开发方面的潜力而引起人们极大的兴趣。本研究描述了芳基重氮乙酸酯与[2.2]对环芳烷的铑催化反应范围。与母体[2.2]对环芳烷的反应导致在两个位置发生环丙烷化,其比例是由催化剂控制的。由于系统中的应变,其中一种环丙烷主要以去甲二烯结构存在,而另一种则优先以环庚三烯构象异构体存在。相反,与[3.3]对环芳烷的反应导致苄基C-H官能化。使用手性催化剂与取代的[2.2]对环芳烃的反应可导致动力学拆分或去对称化。 Rh 2 ( S - p -PhTPCP)] 4催化的单取代对环芳烷反应可导致动力学拆分,选择性 ( s ) 因子高达 20,而用 Rh 2 ( S -TPPTTL) 4 [TPPTTL = 2-(1,3-二氧代-4,5,6,7-四苯基异吲哚啉-2-基)-3,3-二甲基丁酸酯] 可有效去对称化,形成 78 中结合环庚三烯的对环芳烷–98%