Biswal Priyabrata, Siva Subramani M, Samser Shaikh, Chandrasekhar Vadapalli, Venkatasubbaiah Krishnan
School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, an OCC of Homi Bhabha National Institute, Bhubaneswar-752050, Odisha, India.
Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500046, India.
J Org Chem. 2023 Apr 21;88(8):5135-5146. doi: 10.1021/acs.joc.2c00653. Epub 2022 Jun 13.
Herein we report simple, highly efficient, and phosphine-free N,C-Ru and N,N-Ru catalysts for ligand-controlled borrowing-hydrogen (BH) and interrupted-borrowing-hydrogen (I-BH) methods, respectively. This protocol has been employed on a variety of ketones using MeOH as a green, sustainable, and alternative C1 source to form a C-C bond through the BH and I-BH methods. Reasonably good substrate scope, functional group tolerance, and good-to-excellent yields at 70 °C are the added highlights of these methodologies. Controlled experiments reveal that an in situ formed formaldehyde is one of the crucial elements in this ligand-controlled selective protocol, which upon reaction with a ketone generates an enone as an intermediate. This enone in the presence of the N,C-Ru catalyst and N,N-Ru catalyst through the BH and I-BH pathways yields methylated ketones and 1,5-diketones, respectively.
在此，我们分别报道了用于配体控制的借氢（BH）和间断借氢（I-BH）方法的简单、高效且无膦的N，C-Ru和N，N-Ru催化剂。该方案已应用于多种酮类，使用甲醇作为绿色、可持续的替代C1源，通过BH和I-BH方法形成C-C键。合理的底物范围、官能团耐受性以及在70℃下良好至优异的产率是这些方法的额外亮点。对照实验表明，原位形成的甲醛是该配体控制的选择性方案中的关键要素之一，其与酮反应生成烯酮作为中间体。该烯酮在N，C-Ru催化剂和N，N-Ru催化剂存在下，分别通过BH和I-BH途径生成甲基化酮和1，5-二酮。
