3-thiophene- and 3-furancarboxylic acids efficiently undergo perarylation accompanied by cleavage of the three C-H bonds and decarboxylation upon treatment with excess aryl bromides in the presence of a palladium catalyst to give the corresponding tetraarylated products in good yields.

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.

A small library of tetrasubstituted [10]cycloparaphenylene ([10]CPP) derivatives bearing alkyl, alkenyl, alkynyl and aryl substituents was constructed by a Pd‐catalyzed cross‐coupling reaction starting from tetratriflate [10]CPP 5 e, which was readily available in high yields on a >2 g scale. The CPP skeleton increases the reactivity of aryl triflate for oxidative addition to the Pd species, and 5 e is 10 times more reactive than its linear paraphenylene analogue, as determined by competition experiments. Theoretical calculations suggest that the accumulation of the small strain relief from each paraphenylene unit not involved in the reaction is responsible for the observed enhanced reactivity.

Thiophene derivatives R 0090 Palladium-Catalyzed Selective 2,3-Diarylation of α,α-Disubstituted 3-Thiophenemethanols via Cleavage of C-H and C-C Bonds. -In the presence of Pd(O-Ac) 2 and a bulky phosphine, 3-thiophenemethanols of type (I) and their benzothiophene analogues undergo selective diarylation. -(NAKANO, M.; SATOH, T.; MIURA*, M.; J. Org. Chem. 71 (2006) 21, 8309-8311; Dep. Appl. Chem., Fac. Eng.