Direct Sp3α-C–H activation and functionalization of alcohol and ether

Abstract

Seven kinds of sp(3)α-C-H activation/C-C formation reactions of alcohols and ethers have been reviewed in this tutorial review, from the viewpoint of both methodology and synthetic application, towards the efficiency, chemo-, regio- and stereoselectivity, catalytic system, substrate scope and mechanistic study. Section 2 describes radical-mediated α-C-H activation and addition/elimination of ethers with unsaturated (C=C and C[triple bond]C) species. Sections 3-8 discuss the α-C-H activation and additions of alcohols and/or ethers with unsaturated (C=C, C[triple bond]C, C=O and C=N) compounds, which involve the key processes of radical mediation, carbenoid insertion, 1,5-H-migration, oxidative dehydrogenation coupling, transfer hydrogenative coupling, and metal-mediated C=C insertion into the C-H bond.

Activation of CH Bonds through Oxidant‐Free Photoredox Catalysis: Cross‐Coupling Hydrogen‐Evolution Transformation of Isochromans and β‐Keto Esters

“…[2] However,t his activation is much more challenging than the well-established activation of aC ÀHb ond adjacent to an Na tom owingt oi ts highero xidation potential. [3] To realize this type of CÀHb ond activation, stoichiometric amountso fa no xidant, such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)o raperoxide, are alwaysr equired to remove an electron and ah ydrogen atom of the ether,t hereby leading to the formation of an a-oxy radicalo ra no xonium intermediate for subsequentt ransformations under thermals yntheticc onditions (Scheme 1).…”

“…[3] To realize this type of CÀHb ond activation, stoichiometric amountso fa no xidant, such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)o raperoxide, are alwaysr equired to remove an electron and ah ydrogen atom of the ether,t hereby leading to the formation of an a-oxy radicalo ra no xonium intermediate for subsequentt ransformations under thermals yntheticc onditions (Scheme 1). [2][3][4] Recently,the use of visible-light catalysis as acomplementary strategyf or the functionalization of C(sp 3 )ÀHb onds has achieved ab road range of bond-forming reactions.…”

Recent advances on nickel-catalyzed C–H bonds functionalized reactions

“…β-Hydride elimination and reductive elimination affords the observed 1,3-diene. The combination of Ni(cod) 2 and IDTB catalyzes the cycloisomerization of enynes to synthetically valuable cyclic 1,3-dienes. Deuterium labeling studies suggest that the active catalyst species is a Ni-H species generated via a rare Ni(0) C-H activation.…”

“…[1][2][3][4][5][6][7] A relatively inert C-H bond is activated, and the hydrogen atom acts essentially as a leaving group. This technology allows one to bypass the installation and subsequent removal of classical leaving groups and to reduce wastes as well as some precautions (such as protecting group manipulations) typical in the handling of promiscuous amine reagents.…”

Recent achievements in intermolecular sp3 C–H bond functionalization of organic compounds by superelectrophilic trihalomethyl metal complex

“…Functionalization of α sp 3 C−H bond in amines was summarized in several reviews [22]. Functionalization of alcohols and ethers was considered in review [23]. The application of metal carbenoids and nitrenoids for catalytic C−H functionalization was the topic of review [24].…”