Abstract:
This study demonstrates the feasibility and inherent benefits of combining two distinct asymmetric transition-metal-catalyzed reactions in one pot. The reported transformation features a Pd-catalyzed asymmetric allylic alkylation and a Rh-catalyzed enantioselective 1,4-conjugate addition, effectively converting simple allyl enol carbonate precursors into enantioenriched cyclic ketones with two remote stereocenters. Despite the anticipated challenges associated with controlling stereoselectivity in such a complex system, the products are obtained in enantiomeric excesses ranging up to >99 % ee, exceeding those obtained from either of the individual asymmetric reactions. In addition, since the stereoselectivity of both steps is under catalyst control, this one-pot reaction is enantio- and diastereodivergent, enabling facile access to all stereoisomers from the same set of starting materials.
摘要:
这项研究证明了在一个锅中结合两个不同的不对称过渡金属催化反应的可行性和固有的好处。报道的转化具有Pd催化的不对称烯丙基烷基化和Rh催化的对映选择性1,4-共轭加成,有效地将简单的烯丙醇碳酸酯前体转化为具有两个远程立体中心的富含对映体的环酮。尽管在如此复杂的系统中控制立体选择性存在预期的挑战,产品在对映体过量中获得,范围高达>99%ee,超过从任何一个单独的不对称反应获得的那些。此外,由于这两个步骤的立体选择性都在催化剂控制下,这种一锅法反应是对映体和非对映反应,使得能够从同一组起始材料容易地获得所有立体异构体。