Synthesis of ethynylated biaryls and asymmetric diethynylated benzene via sequential Sonogashira and Suzuki couplings in water

Abstract

Two 1-bromo-4-ethynylbenzene candidates were synthesized from 1-bromo-4-iodobenzene via Sonogashira coupling then sequentially employed in Suzuki coupling with arylboronic acids in water to give ethynylated biaryl derivatives. Optimization of the reaction condition was done using two different palladium sources and various bases/solvents systems. Further sequential Sonogashira coupling of 1-bromo-4-ethynylbenzene candidates, in aqueous medium, afforded asymmetric diethynylated benzene derivatives.

Microwave promoted Heck and Suzuki coupling reactions of new 3-(5-bromobenzofuranyl)pyrazole in aqueous media

“…In continuation of our research work on the use of palladium(II) complexes under microwave irradiation for Suzuki-Miyaura, Heck-Mizoroki, and Sonogashira cross-coupling reactions, [33][34][35][36][37][38][39][40][41][42][43][44] we report, herein, the use of the benzothiazole-oxime palladium(II) complex (4) as a pre-catalyst for the Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions of 3-(5-bromobenzofuran-2-yl)-1H-pyrazole (3) under thermal heating and microwave irradiation in aqueous media.…”