Palladium-Catalyzed Selective 2,3-Diarylation of α,α-Disubstituted 3-Thiophenemethanols via Cleavage of C−H and C−C Bonds

Abstract

Alpha,alpha-disubstituted 3-thiophenemethanols undergo selective diarylation accompanied by cleavage of the C-H and C-C bonds of the 2- and 3-positions, respectively, upon treatment with aryl bromides in the presence of a palladium catalyst to give the corresponding 2,3-diarylthiophenes in good yields.

Catalytic C–C coupling through C–H arylation of arenes or heteroarenes

“…Thus, as shown in Scheme 21,˛,˛-diphenyl-3-thiophenemethanol and bromobenzene were converted into 2,3-diphenylthiophene in 86% yield. Only a minor amount (10%) of 2,3,5-triphenylthiophene was formed [90].…”

The Aromatic Carbon–Carbon ipso‐Substitution Reaction

“…Next, Miura et al [20] studied the selective 2,3-diarylation reaction of 2-(thienyl-3-yl)-2-propanol, a,a-diphenyl(thienyl-3-yl)methanol, and 2-(benzo [b]thienyl-3-yl)-2-propanol by means of cleavage of the CÀH and CÀC bonds in the 2-and 3-positions, respectively. This reaction provided a useful route to the synthesis of 2,3-diarylthiophenes and 2,3-diarylbenzo [b]thiophenes by treatment of the carbinol (0.5 mmol) with an aryl bromide (2 mmol) in the presence of PdA C H T U N G T R E N N U N G (OAc) 2 (10 mol %), P(biphenyl-2-yl)A C H T U N G T R E N N U N G (tBu) 2 (20 mol %), Cs 2 CO 3 (2 mmol) in toluene heated at reflux or o-xylene under N 2 for 10 h. Kotschy and co-workers, [21] however, reported a less clear-cut reaction when applying the procedure of Miuras group on the reaction between a,a-diphenyl-(thienyl-3-yl)methanol and bromobenzene.…”

Fluorescent Diarylindoles by Palladium‐Catalyzed Direct and Decarboxylative Arylations of Carboxyindoles

“…[12] This synthetic strategy involves sequential ortho-and ipso-arylations, [12][13][14] and gratifyingly, it has been successfully utilized in carboxyindole systems. Herein, we report the palladiumcatalyzed 2,3-diarylation of carboxyindole derivatives with aryl bromides, as well as a practical route to 2,3-diarylindoles having different aryl substituents by performing ester hydrolysis in the sequence.…”