Visible‐Light‐Catalyzed Direct Benzylic C(sp³)–H Amination Reaction by Cross‐Dehydrogenative Coupling

Abstract

Aconceptually new and synthetically valuable crossdehydrogenative benzylic C(sp 3 )-H amination reaction is reported by visible-light photoredox catalysis.T his protocol employs DCA( 9,10-dicyanoanthracene) as av isible-lightabsorbing photoredoxc atalyst and an amide as the nitrogen source without the need of either at ransition metal or an external oxidant.

Organocatalysis in Inert C–H Bond Functionalization

“…Pandey and co-workers developed a photoredox catalytic protocol for benzyl C−O formation via C−H activation. 167,168 In the presence of 1,4-dicyanonaphthalene (DCN) under irradiation with a 450 W lamp (>300 nm hemiacetals with water as the source of oxygen. This protocol also could be employed for direct transformation of arylalkyls into the corresponding aryl ketones (Scheme 122, 122d).…”

“…In 2015, Pandey and Laha developed a successful crossdehydrogenative benzylic C−H amination by using DCA (9,10dicyanoanthracene) as a photoredox catalyst under aerobic conditions (Scheme 123). 168 The methoxy group present in the amide substrate was necessary for generating the desired product. Aminated products were obtained with a wide range of benzyl C−H bonds in moderate yields and excellent regioselectivity.…”

Benzylic C−H acylation by cooperative NHC and photoredox catalysis

“…Benzylic C–H bonds occur in many bioactive compounds and ~25% of the top-selling 200 pharmaceuticals contain this structural motif 5 , 6 . Great efforts have been devoted to functionalize such C–H bonds and benzylic C–C 7 – 11 , C–N 12 – 14 , C–O 15 – 18 , and C–F bond 19 , 20 formation among others 21 , 22 have been realized. However, direct benzylic C–H bond acylation is not well explored.…”

Copper-Catalyzed Benzylic C–H Bond Thiocyanation: Enabling Late-Stage Diversifications

“…[1][2][3][4][5] Specifically, selective functionalization of the ubiquitous benzylic C-H bond in organic molecules has a broad impact, ranging from upgrading feedstock alkylarenes for functional molecule synthesis to late-stage modifications of complex pharmaceuticals and bioactive structures (Scheme 1a). [6][7][8][9][10][11][12][13][14][15][16][17][18] For instance, approximately 30% of the top-selling drugs contain at least one (hetero)benzylic C-H bond, and the selective functionalization of these C-H bonds could potentially change their metabolic stabilities and regulate bioactivities. Information gathered by the Njardarson group with data from DrugTopics & Pharmacompass.…”