Sakai Kotaro, Lyu Yanzong, Odake Jun, Toriumi Naoyuki, Iwasawa Nobuharu, Uchiyama Masanobu
Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Department of Chemistry, Institute of Science Tokyo, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan.
Sci Adv. 2025 Sep 12;11(37):eadz5235. doi: 10.1126/sciadv.adz5235.
Cross-dehydrogenative coupling (CDC) between two C─H bonds without any oxidant would be an excellent C─C bond-forming reaction, generating H as the only by-product. However, C(sp)─H/C(sp)─H CDC reactions remain rare despite the rapid development of transition metal catalysis, photocatalysis, and electrocatalysis. Here, we describe directing-group- and oxidant-free C(sp)─H/C(sp)─H CDC between arenes and styrenes/furans photocatalyzed by a PSP-pincer Rh complex to afford stilbenes/heterobiaryls under mild conditions (blue light irradiation, near room temperature). The reaction is applicable to a wide range of substrates, and undesired hydrogenation of the styrenes and stilbenes is strongly suppressed. The generated H gas can be used for hydrogenation of alkenes in a connected flask system. Experimental mechanistic studies indicated that the Rh(I)─Ar complex is a key intermediate in the catalytic cycle, and C(sp)─H bond cleavage of the styrenes/furans occurs via oxidative addition in the excited state.
在没有任何氧化剂的情况下，两个碳氢键之间的交叉脱氢偶联（CDC）将是一种出色的碳-碳键形成反应，仅产生氢气作为副产物。然而，尽管过渡金属催化、光催化和电催化发展迅速，但碳（sp）-氢/碳（sp）-氢的CDC反应仍然很少见。在此，我们描述了一种由PSP钳形铑配合物光催化的芳烃与苯乙烯/呋喃之间的无导向基团和无氧化剂的碳（sp）-氢/碳（sp）-氢CDC反应，在温和条件下（蓝光照射，接近室温）生成二苯乙烯/杂联芳基。该反应适用于多种底物，并且强烈抑制了苯乙烯和二苯乙烯不希望发生的氢化反应。生成的氢气可用于在连接烧瓶系统中烯烃的氢化反应。实验机理研究表明，铑（I）-芳基配合物是催化循环中的关键中间体，苯乙烯/呋喃的碳（sp）-氢键裂解通过激发态的氧化加成发生。
