Zhao Gaoyuan, Khosravi Arman, Sharma Sahil, Musaev Djamaladdin G, Ngai Ming-Yu
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
J Am Chem Soc. 2024 Nov 20;146(46):31391-31399. doi: 10.1021/jacs.4c12583. Epub 2024 Nov 12.
The alkene-carboxylate transposition (ACT) of allyl carboxylates is one of the most atom-economic and synthetically reliable transformations in organic chemistry, as allyl carboxylates are versatile synthetic intermediates. Classic ACT transformations, including [3,3]-sigmatropic rearrangement and transition metal-catalyzed allylic rearrangement, typically yield 1,2-alkene/1,3-acyloxy shifted products through a two-electron process. However, position-altered ACT to produce distinct 1,3-alkene/1,2-acyloxy shifted products remains elusive. Here, we report the first cobalt-hydride-catalyzed ACT of allyl carboxylates, enabling access to these unprecedented 1,3-alkene/1,2-acyloxy shifted products via a 1,2-radical migration (RaM) strategy. This transformation demonstrates broad functional group tolerance, is suitable for late-stage modification of complex molecules, and is amenable to gram-scale synthesis. It also expands the reaction profiles of both allyl carboxylates and cobalt catalysis. Preliminary experimental and computational studies suggest a mechanism involving metal-hydride hydrogen atom transfer (MHAT) and the 1,2-RaM process. This reaction is expected to serve as the basis for the development of versatile Co-H-catalyzed transformations of allyl carboxylates, generating a wide array of valuable building blocks for synthetic, medicinal, and materials chemistry.
烯丙基羧酸盐的烯烃-羧酸盐换位反应（ACT）是有机化学中原子经济性最高且合成可靠性最强的转化反应之一，因为烯丙基羧酸盐是用途广泛的合成中间体。经典的ACT转化反应，包括[3,3]-σ迁移重排和过渡金属催化的烯丙基重排，通常通过双电子过程生成1,2-烯烃/1,3-酰氧基迁移产物。然而，生成不同的1,3-烯烃/1,2-酰氧基迁移产物的位置改变型ACT仍然难以实现。在此，我们报道了首例钴氢化物催化的烯丙基羧酸盐ACT反应，通过1,2-自由基迁移（RaM）策略能够得到这些前所未有的1,3-烯烃/1,2-酰氧基迁移产物。该转化反应具有广泛的官能团耐受性，适用于复杂分子的后期修饰，并且适合克级规模的合成。它还拓展了烯丙基羧酸盐和钴催化的反应类型。初步的实验和计算研究表明其机理涉及金属氢化物氢原子转移（MHAT）和1,2-RaM过程。预计该反应将成为开发烯丙基羧酸盐通用钴氢催化转化反应的基础，为合成化学、药物化学和材料化学生成一系列有价值的结构单元。
