Dominguez-Molano Paula, Weeks Rosemary, Maza Ricardo J, Carbó Jorge J, Fernández Elena
Department Química Física i Inorgànica, Universitat Rovira i Virgili, 43007, Tarragona, Spain.
Department Chemistry, Edinburgh University, EH8 9YL, Edinburgh, UK.
Angew Chem Int Ed Engl. 2023 Jul 24;62(30):e202304791. doi: 10.1002/anie.202304791. Epub 2023 Jun 14.
Regioselective borylcupration of borylated skipped (Z)-dienes generates diborylated alkylcopper species that are involved in an intramolecular stereospecific B/Cu 1,3-rearrangement by migration of Bpin moiety from C(sp ) to C(sp ). DFT mechanistic studies showed that boryl migration occurs through the formation of 4-membered boracycle intermediate with a moderate free-energy barrier. Moreover, the use of KOMe forms stable Lewis base adducts with Bpin moieties that blocks the reaction. Subsequently to the 1,3-boron shift, the in situ electrophilic trapping allows selective C-H, C-C and C-X bonds, followed by intramolecular cross coupling giving access to cyclic functionalized alkylidenecyclohexanes or alkylidenecyclobutanes.
硼化的(Z)-跳跃二烯的区域选择性硼铜化反应生成二硼化烷基铜物种，这些物种通过硼酸频哪醇酯基团从C(sp)迁移到C(sp)参与分子内立体专一性的硼/铜1,3-重排反应。密度泛函理论机理研究表明，硼迁移通过形成具有适度自由能垒的四元硼杂环中间体发生。此外，使用甲氧基钾会与硼酸频哪醇酯基团形成稳定的路易斯碱加合物，从而阻碍反应。在1,3-硼迁移之后，原位亲电捕获允许选择性地形成碳-氢键、碳-碳键和碳-卤键，随后进行分子内交叉偶联反应，得到环状官能化的亚烷基环己烷或亚烷基环丁烷。
