AbstractHerein, we present a manganese‐catalyzed, branched‐selective hydroalkenylation of terminal alkynes, under mild conditions through facile installation of a versatile silanol as a removable directing group. With an alkenyl boronic acid as the coupling partner, this reaction produces stereodefined (E,E)‐1,3‐dienes with high regio‐, chemo‐ and stereoselectivity. The protocol features mild reaction conditions such as room temperature and an air atmosphere, while maintaining excellent functional group compatibility. The resulting 1,3‐dienesilanol products serve as versatile building blocks, as the removal of the silanol group allows for the synthesis of both branched terminal 1,3‐dienes for downstream coupling reactions, as well as stereoselective construction of linear (E,E)‐1,3‐dienes and (E,E,E)‐ or (E,E,Z)‐1,3,5‐trienes. In addition, a Diels–Alder cycloaddition can smoothly and selectively deliver silicon‐containing pentasubstituted cyclohexene derivatives. Mechanistic investigations, in conjunction with DFT calculations, suggest a bimetallic synergistic activation model to account for the observed enhanced catalytic efficiency and good regioselectivity.
摘要在此,我们介绍了一种锰催化的、支链选择性的末端炔烃加氢烯化反应,该反应是在温和的条件下,通过简便地安装一个多功能硅醇作为可移动的指导基团而实现的。以烯基硼酸为偶联剂,该反应可生成立体定向的 (E,E)-1,3-二烯,并具有高度的区域、化学和立体选择性。该方案的反应条件温和,如室温和空气环境,同时保持了极好的官能团兼容性。生成的 1,3-二烯硅烷醇产品可作为多功能构筑基块,因为去除硅烷醇基团可合成用于下游偶联反应的支链末端 1,3-二烯,以及立体选择性地构建线性 (E,E)-1,3 二烯和 (E,E,E)- 或 (E,E,Z)-1,3,5 三烯。此外,Diels-Alder 环化反应还能顺利地、选择性地生成含硅的五取代环己烯衍生物。结合 DFT 计算进行的机理研究表明,双金属协同活化模型可以解释所观察到的更高催化效率和良好的区域选择性。