The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24000
<sup><i>t</i></sup>BuOK-Promoted Cyclization of Imines with Aryl Halides
作者:Ya-Wei Li、Hong-Xing Zheng、Bo Yang、Xiang-Huan Shan、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1021/acs.orglett.0c01615
日期:2020.6.5
A transition-metal-free indole synthesis using radical coupling of 2-halotoluenes and imines via the later-stage C–N bond construction was reported for the first time. It includes an aminyl radical generation by C–H cleaving addition of 2-halotoluenes to imines via the carbanion radical relay and an intramolecular coupling of aryl halides with aminyl radicals. One standard condition can be used for
Although quaternary ammonium and phosphonium salts are known as important catalysts in phase-transfer catalysis, the catalytic ability of tertiary sulfonium salts has not yet been well demonstrated. Herein, we demonstrate...
Metal–Ligand Cooperation Facilitates Bond Activation and Catalytic Hydrogenation with Zinc Pincer Complexes
作者:Michael Rauch、Sayan Kar、Amit Kumar、Liat Avram、Linda J. W. Shimon、David Milstein
DOI:10.1021/jacs.0c05500
日期:2020.8.26
A series of PNP zinc pincer complexes capable of bondactivation via aromatization/dearomatization metal–ligand cooperation (MLC) were prepared and characterized. Reversible heterolytic N–H and H–H bondactivation by MLC is shown, in which hemilability of the phosphorus linkers plays a key role. Utilizing this zinc pincer system, base-free catalytic hydrogenation of imines and ketones is demonstrated