Nickel-catalyzed thiolation of unactivated aryl C–H bonds: efficient access to diverse aryl sulfides

Abstract

A nickel-catalyzed thiolation of unactivated C(sp(2))-H bonds with disulfides employing the PIP directing group was described. This process uses a catalytic nickel catalyst and no metallic oxidants or cocatalysts are required. The reaction tolerates various important functional groups and heteroarenes, providing an efficient synthetic pathway to access diverse diaryl sulfides.

BINOL accelerated Ru(II)-catalyzed regioselective C-H functionalization of arenes with disulfides and diselenides

“…Subsequent screening with ligand led to accelerating the reaction to produce 3a in 72% yield employing BINOL, whereas PCy 3 , bipyridyl and Boc-Phe-OH showed inferior results (entries 2-5). Toluene was found to be the solvent of choice, while 1,4-dioxane, DMF, (CH 2 Cl) 2 , m-xylene and chlorobenzene furnished \42% yield (entries [6][7][8][9][10]. In a set of oxidants studied, Ag 2 CO 3 , AgOAc, Cu(OAc) 2 , K 2 S 2 O 8 , Ag 2 O and AgNO 3 , the former gave the best result (entries [11][12][13][14][15].…”

“…6 In 2006, Yu and co-workers demonstrated a Cu-catalyzed C-H thiolation of 2-phenylpyridines utilizing disulfides. 7a Since then, efforts are made on the directing group assisted C-H functionalization of arenes with disulfides using Cu, 7 Co, 8 Ni, 9 Rh, 10 Ru 11 and Pd 12 -based catalytic systems. 7-Azaindoles are important structural scaffolds found in a plethora of bioactive natural products and marketed drugs.…”

Nickel-Catalyzed C–H Bond Functionalization Utilizing an N,N′-Bidentate Directing Group

“…Lu (Scheme 17a) [43] and Shi (Scheme 17b) [44] used a PIP directing group and Zhang used an 8-aminoquinoline as the directing group (Scheme 17c) [45]. In all cases, the reactions showed a high degree of functional group tolerance.…”

α,α-Dimethyl-2-pyridinemethanamine

“…5 It has been proposed that the gemdimethyl substitution may increase the rate of cyclization and the stability of the resulting metallacycles due to the Thorpe-Ingold effect. 5, 6 The PIP auxiliary has been widely used for the cleavage of C-H bonds and the formation of C-O, 7-9 C-C, 1b,2,10-15 C-N, 1b C-S, [16][17][18][19] and C-X 20,21 bonds. Various transition metals, such as palladium, copper, and nickel, have been used for these transformations.…”