Hiyama reaction of aryl bromides with arylsiloxanes catalyzed by a reusable palladium(II)/cationic bipyridyl system in water

Hiyama cross‐coupling reaction catalyzed by a palladium salt of 1‐benzyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride under microwave irradiation

“…[9][10][11][12] Transition-metal catalyzed cross-coupling reactions typically need long reaction times and an inert atmosphere to reach completion with traditional heating. In comparison with other organometallic reagents employed for the preparation of biaryls, organosilanes are very attractive due to their low cost and toxicity, ease of handling and stability in various chemical media.…”

Microwave-assisted Stille and Hiyama cross-coupling reactions catalyzed by ortho-palladated complexes of homoveratrylamine

“…An increase in hindrance in the vicinity of the leaving group results in a decrease in the conversion (Table 2, entries 9-11). The chemoselectivity of the procedure was examined using bromo-chlorobenzenes (Table 2, entries [12][13][14]. In these reactions Br acted as the better leaving group.…”

“…The symmetrical and unsymmetrical biaryls synthesized in this work have been reported previously and were characterized by comparing their mp, and IR, 1 H, and 13 C NMR spectra with those found in the literature. 14,27,32 …”

“…Due to the low reactivity of these reagents, they typically need to be activated by fluoride in order to generate a more reactive pentacoordinate silicate anion for the transmetallation step. [13][14][15] Generally, the combination of palladium catalysts with various phosphine ligands and also N-heterocyclic carbenes (NHC) results in excellent yields and high efficiency in cross-coupling reactions. However, most phosphine ligands are air and moisture sensitive, and economically and environmentally undesirable due to difficulties with their recovery and the formation of toxic phosphines as by-products in these reactions.…”

Application of a dimeric ortho‐palladated complex of tribenzylamine as an efficient catalyst in microwave‐assisted Hiyama coupling reactions

“…Because of the low reactivity of organosilanes, the reaction generally requires fluoride anions for activation of the stable silicon–carbon bond to facilitate the transmetallation step in the catalytic cycle . Many efforts have focused on the development of efficient and selective catalytic systems for this transformation using various palladium catalysts and fluoride derivatives . A few phosphine‐free Hiyama coupling reactions using N ‐ligand‐based palladium catalysts have been reported .…”