Ru-catalyzed directed o-C–H arylation reactions of 2-phenylpyridine, N-phenylpyrazole, acetophenone N-(p-methoxyphenyl)imine, and 2-phenyloxazoline proceed in good to excellent yields with a number of functionalized aryl and heteroaryl bromides in neat Bu4NOAc… Click to show full abstract
Ru-catalyzed directed o-C–H arylation reactions of 2-phenylpyridine, N-phenylpyrazole, acetophenone N-(p-methoxyphenyl)imine, and 2-phenyloxazoline proceed in good to excellent yields with a number of functionalized aryl and heteroaryl bromides in neat Bu4NOAc at 120 °C. The acetate ion acts as the base and the relatively low melting point Bu4N salts (a mixture of acetate and bromide) behave as an ionic liquid. Arylation reactions of 2-phenyloxazoline proceed with concomitant oxazolidine cleavage to give 2-(N-acetylamino)ethyl benzoates promoted by side product CH3COOH. The dual-purpose ionic liquid medium is compatible with both ligandless Ru for di-arylation (optimal pre-catalyst: RuCl3·xH2O) and Ru-phosphane (optimal pre-catalyst: [RuCl2(p-cymene)]2/P(p-Tol)3 1:4) catalysts (1–5 mol-%) for selective mono-arylation.
               
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