Hiyama reaction palladium-catalyzed

The Hiyama Coupling is the palladium-catalyzed C-C bond formation between aryl, alkenyl, or alkyl halides or pseudohalides and organosilanes. This reaction is comparable to the Suzuki Coupling and also requires an activating agent such as fluoride ion or a base. 

Tsuji-Trost allylation reactions offer multiple pathways to tetrahydrofuran synthesis including C-C bond-formation steps. A palladium-catalyzed sequence of allylic alkylation and Hiyama cross-coupling provides a convenient synthesis of 4-(styryl)-lactones (Scheme 67) <2006SL2231>. 

Denmark and his co-workers recently reported a series of the palladium-catalyzed coupling reactions of alkenylsilicon compounds with aryl iodides. Thus, ( )- or (Z)-alkenylsilacyclobutanes, which are readily prepared by the reaction of the corresponding alkenylaluminum compounds with chlorosila-cylobutanes or the reduction of alkynylsilacyclobutanes, respectively, were found to be active nucleophiles to react with aryl iodides in 10 min at room temperature in most cases (Eq. 13) [17]. Later, it was clarified that silacyclobu-tanes were first converted into alkenyl(propyl)silanols by hydrolysis under the reaction conditions [18], and these were shown to be truly active species. Alkenylsilanols actually react with aryl iodides under the similar conditions (Eq. 14) [19,20]. Independent study by Hiyama and Mori revealed that silver(l) oxide also is an excellent activator for the palladium-catalyzed coupling of alkenylsilanols with an aryl iodide (Eq. 15) [21]. Very recently Denmark... 

The use of alkenylsilyl ethers in palladium-catalyzed cross-coupHng reactions has long been known. In fact, only a year after Hiyama s landmark report on the TBAF-promoted coupling reactions of vinyltrimethylsilane, Tamao and Ito capitahzed on the use of alkoxy-substituted silanes as viable components for such reactions (cf Scheme 7.4). The generahty of the silyl ether coupHng added a useful class of organosilicon substrates that are complementary to the fluorosilanes developed by Hiyama et al. These studies showed that other heteroatom-based... 

The palladium-catalyzed Hiyama reaction is a cross-coupling between aryl halides and silanes (Scheme 19.47) [65]. Silane derivatives are easily available. They are stable with a low toxicity. However, they exhibit a low reactivity, and the reactions must be performed at high temperatures. Reactions are promoted by fluoride ions [65]. 

Fluoride-free Hiyama cross-coupling reactions of phenyltrimethoxysilane with aryl halides was performed in water using sodium hydroxide as activator at 110°C under microwave heating [32]. The reaction was catalyzed by poly (N-viityl-2-pyrrolidone) (PVP)-stabilized colloidal palladium NPs. The reaction proceeds quickly under microwave heating (6 min). 

Chen SN, Wu WY, Tsai FY (2008) Hiyama reaction of aryl bromides with arylsiloxanes catalyzed by a reusable palladium(II)/cationic bipyridyl system in water. Tetrahedron 64(35) 8164-8168... 

Shimizu and Hiyama [129] reported that the palladium-catalyzed double-cross-coupling reaction of 9-stannafluorenes 213 with 1,1-dihaloethylene 214 yields the dibenzofulvene 215 (Scheme 6.57a). The 9-staimafluorene 213, an equivalent of a 1,4-dimetalated reagent, is available from the corresponding 2,2 -dihalobiphenyls. The reaction was applied to the synthesis of the jt-extended fulvalene derivative 217 from 216. The former is a stable benzaimulated Chichibabin hydrocarbon possessing an open-shell diradical character (Scheme 6.57b) [130]. 

The palladium-catalyzed reaction of alkenyl-, aryl-, alkynyl- and alkylsiloxanes with aryl, alkyl, and alkenyl halides and triflates in the presence of activators is known as the Hiyama cross-coupling reaction and several reviews have been published. This chapter will present major developments and examples of recent carbon-carbon bond formation methodology and improvements as well as their use in natural products synthesis in the last few years. 

To date, nearly all studies of the Hiyama reaction have focused on couplings of Csp -X electrophiles. Fu developed the first method for achieving the room-temperature Hiyama couplings of unactivated alkyl bromides and iodides. Palladium-catalyzed reactions of alkyl bromides and iodides 18 with aryltrimethoxysilanes 19 in the presence of phosphorus ligand and TBAF afforded coupled products 20 in moderate to good yields. 

Marciniec demonstrated that 9-vinycarbazole (49) can undergo crossmetathesis with vinyltriethoxysilane with the ruthenium catalyst to give vinylsiloxane carbazole 50 which then participated in a Hiyama palladium-catalyzed reaction with aryl iodides to furnish ( )-A-styrylcarbazoles 51. ... 

A colloidal palladium nanoparticle prepared from a Fischer carbene complex of tungsten with K2PdCl4 as the reductant and PEG as the capping agent, efficiently catalyzed the Hiyama cross-coupling reactions in air. ... 

Shah and Kaur (2012) reported a nonfunctional macroporous commercial resin, Amberlite XAD-4, impregnated with palladium nanoparticles (PdNPs) of size 5-10 nm. These supported Pd nanoparticles were used to catalyze the sodium hydroxide activated Hiyama cross-coupling reaction of phenyltrimethoxysilane with a variety of bromo and chloroarenes under microwave heating. These were found to have... 

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