Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reaction in Water by Visible Light

Abstract

By using catalytic amount of CoCl2 with dmgH (dimethylglyoxime) as ligand to form a photosensitizer in situ, a highly selective, efficient, and environmentally benign visible light mediated cross-dehydrogenative coupling (CDC) reaction has been developed in aqueous medium. The desired cross-coupling C-C bonds that involve Csp3 with Csp, Csp2, and Csp3, respectively, were achieved exclusively in high yields without formation of any other byproduct.

Aerobic Oxidative Functionalization of Indoles

“…In 2015, Wu et al discovered a visible-lightinduced cobalt-catalyzed CDC reaction of indoles and tetrahydroisoquinolines in aqueous medium with irradiation of blue LEDs (Scheme 20, conditions D). [53] In this protocol, earth-abundant and simple cobalt salts with dmgH as a ligand was used to form in situ a photosensitizer. Hence, good to excellent yields of the desired cross-coupling products were observed in the aerobic conditions at room temperature.…”

Visible‐Light‐Assisted Cobalt‐2‐(hydroxyimino)‐1‐phenylpropan‐1‐one Complex Catalyzed Pd/Cu‐Free Sonogashira–Hagihara Cross‐Coupling Reaction

“…Currently, photocatalysis driven by visible light has emerged as a mild and efficient catalytic approach in the realm of organic synthesis . Compared with the conventional heating method, the numerous visible‐light‐catalyzed reactions have the clear advantages of being clean, sustainable, and environmentally benign.…”

9,10-Phenanthrenedione as Visible-Light Photoredox Catalyst: A Green Methodology for the Functionalization of 3,4-Dihydro-1,4-Benzoxazin-2-ones through a Friedel-Crafts Reaction

“…[39][40][41][42] Normally, this sp 3 -C-H functionalization involves the oxidation of the amine to iminium ion, that can be attacked by various kind of nucleophiles. Nonetheless, the major number of examples are regarded to the functionalization of N-aryl tetrahydroisoquinolines, [43][44][45][46][47][48][49][50][51][52][53] N,N-dimethylanilines [54][55][56][57][58] and N-aryl glycine derivatives. [59][60][61][62][63] Hence, exploring other substrates is highly desirable.…”