Reeves Ryan D, Kinkema Caitlin N, Landwehr Eleanor M, Vine Logan E, Schomaker Jennifer M
Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, WI 53706, USA.
Blueprint Medicines, 45 Sidney Street, Cambridge, MA 02139, USA.
Synlett. 2020 Apr;11(6):627-631. doi: 10.1055/s-0037-1610746. Epub 2020 Feb 4.
Metal-catalyzed allene cycloisomerizations provide rapid entry into five-membered carbocyclic frameworks, a common motif in natural products and pharmaceuticals. While both Au(I) and Pd(0)-catalyzed allene cycloisomerizations give 5-- cyclization, Pd prefers the diastereomer in contrast to the isomer observed with Au. The change in stereoselectivity is proposed to arise from buildup of A strain during the key carbopalladation step to furnish the cycloisomerized products in moderate to good with yields comparable to Au(I) catalysts.
金属催化的联烯环异构化反应能够快速构建五元碳环骨架，这是天然产物和药物中常见的结构单元。虽然金（I）和钯（0）催化的联烯环异构化反应都能实现5-环化，但与金催化反应中观察到的异构体相比，钯更倾向于生成非对映异构体。立体选择性的变化被认为是由于在关键的碳钯化步骤中A应变的积累，从而以中等至良好的产率提供环异构化产物，其产率与金（I）催化剂相当。
