Cross-dehydrogenative coupling involving benzylic and allylic C–H bonds

Abstract

Benzylic and allylic C–H bonds are coupled with C(sp)–H, C(sp2)–H and C(sp3)–H bonds in a straightforward and high atom-economic manner.

Benzylic C(sp3)–C(sp2) cross-coupling of indoles enabled by oxidative radical generation and nickel catalysis

“…The expeditious introduction of benzylic radical intermediates to a metal center allows for the efficient generation of metal alkyl species, forming the foundation for subsequent functionalization. 5 Conventionally, radical formation events at the benzylic position have been realized by hydrogen atom transfer (HAT), 6 with recent advances in photoredox catalysis (PC) having greatly broadened the applicability of this method. 7 However, the HAT process generally requires the use of a large excess of substrate due to its insufficient reactivity.…”

Synthesis of2H‐benzo[g]furo/thieno/pyrrolo[2,3‐e]indazolesviaIntramolecular Dehydrogenation Photocyclization

“…Most of the photoinduced cross‐dehydrogenative coupling (CDC) reactions needed oxidants or transition metals. [ 24‐25 ] Photochemical organic synthesis in the absence of photocatalysts, oxidant, base and acid has received great attention due to its economic and synthetic value. [ 26 ]…”

Combustion-Synthesized Porous CuO-CeO2-SiO2 Composites as Solid Catalysts for the Alkenylation of C(sp3)-H Bonds Adjacent to a Heteroatom via Cross-Dehydrogenative Coupling

“…In recent years, cross-dehydrogenative coupling (CDC) to directly build a C-C bond from two simple C-H bonds has emerged as an attractive goal in organic synthesis [1,2]. Offering great benefits including improving atom economy, step efficiency, and reducing cost and waste, the CDC reaction is a more efficient synthetic protocol to access product molecules compared to traditional cross-couplings, which often require the use of prefunctionalized halides and organometallic reagents [1,[3][4][5]. In particular, α-C(sp 3 )-H of ethers and amines can be selectively coupled with C(sp 3 )-H or C(sp 2 )-H, leading to more complex structural motifs which have been usually found in natural products, pharmaceuticals, agrochemicals, biologically active molecules, and functional materials [6][7][8].…”