Water Suzuki-Miyaura coupling

A major advantage of this MCR is that organoboronic acids are readily available in a large variety of structural configurations and they can be formed in isomeri-cally pure forms. As a result of their widespread utility in Suzuki-Miyaura coupling [27, 28] and other reactions [29, 30], a variety of aryl and heteroaryl [31] boronic adds are now commercially available and can be employed in this MCR process. Most of these compounds are also air and water stable as well as non-toxic and environmentally friendly. They also tolerate many functional groups, thereby... 

Scheme 46 Scale-up of a Suzuki-Miyaura coupling in water...

Recently, a paper was published describing Suzuki-Miyaura coupling in DMF and water with aryl chlorides using the air- and moisture-stable... 

Trapping the palladium species by transmetalation in a Suzuki-Miyaura coupling shows a very similar trend (Table 2) [38], By modifying the original Suzuki-Miyaura conditions [54] by the addition of water and pivalic acid [37], the palladium can migrate between the two o-positions before being trapped by... 

A recent paper has described Suzuki-Miyaura couplings of aryl chlorides in DMF and water, using the air and moisture-stable dihydrogen di-yr-chlorodichlorobis(di-tert-butylphosphinito-A P)dipalladate (POPd2) catalyst (Scheme 15.5) [24]. 

Reactions of arylboronic acids with allyl esters have also been found to proceed smoothly in water to give allylic arylation products via a Ti-allylic intermediate with net inversion of configuration (Scheme 22) [90]. It was reported that the secondary allyl esters (alkyl vinyl carbinol esters) undergo j0-hydrogen elimination of the Ti-allylpalladium intermediates forming conjugated dienes under the standard Suzuki-Miyaura coupling conditions due to the relatively lower reactivity of arylboronic acids. 

Polymer-stabilized palladium nanoparticles (or nanoclusters) [125-127] have recently received increasing attention in the field of synthetic organic chemistry [128, 129]. Thus, for example, the poly(iV-vinyl-2-pyrrolidone) (PVP)-supported Pd particle catalyzed the Suzuki-Miyaura coupling in water [130]. Poly(amidoamine) (PAMAM) dendrimer-encapsulated palladium nanoparticles were designed and prepared to provide highly selective catalysts for hydrogenation of olefins [131-133]. Hyperbranched aromatic amides (aramids) and PS-DVB-methacryloylethylenesulfonic acid resin have also been... 

Cross-coupling reactions have also been examined in water using amphiphilic PS-PEG resin-supported palladium complexes. Palladium-catalyzed coupling of aryl halides with aryl(or alkenyl)boronic acids (the so-called Suzuki-Miyaura coupling) took place in aqueous alkaline solution in the presence of polymeric catalyst 59 at 25 °C to give the biaryls in excellent yields [90,... 

The Suzuki-Miyaura coupling can also be performed with a ligandless palladium catalyst, using a mixture of water and ammonium salt 93 or pyrrolidinium salt 94 (Scheme 38). These BF4 salts have high melting points (125°C and 160 C, respectively) but melt in water to form a biphasic mixture at much lower temperatures ( 50 C and 80°C). The recycling was not efficient, but salts 93 and 94 can be separated and purified, unUke the case with standard ionic Uquids. 

Along with their work on the nickel-catalyzed Suzuki-Miyaura coupling of neopentylglycol boronic esters, Percec and coworkers examined the speed of transesterification of a cyclic arylboronic ester with a diol under anhydrous conditions. In both assays in Scheme 3.2, some transesterification had taken place after 10 h (equilibrium was not reached). This result shows that transesterification of cyclic boronic esters is always possible, even starting from pinacol esters. This should be kept in mind when considering reactions in the presence of alcohol solvents and water. 

Scheme 29A Suzuky-Miyaura coupling of chloroarenes in water catalyzed by the NHC-Pd organometallic polymers.

A water-accelerated palladium-catalyzed reaction of gem-dibromoolefins with a boronic acid via a tandem Suzuki-Miyaura coupling and direct arylation was reported [47]. One of the products, 57, corresponded to 7-CF3 derivative of benzoindolizine. 

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