Organic halides Suzuki reaction

Palladium-catalyzed carbon-carbon bond forming reactions like the Suzuki reac-tion as well as the Heck reaction and the Stille reaction, have in recent years gained increased importance in synthetic organic chemistry. In case of the Suzuki reaction, an organoboron compound—usually a boronic acid—is reacted with an aryl (or alkenyl, or alkynyl) halide in the presence of a palladium catalyst. 

The Suzuki reaction (the palladium-catalyzed cross-coupling of aryl halides with boronic acids) is arguably one of the most versatile and at the same time also one of the most often used cross-coupling reactions in modern organic synthesis [32], Carrying out high-speed Suzuki reactions under controlled microwave conditions can today be considered almost a routine synthetic procedure, given the enormous literature precedent for this transformation [7]. 

Three-component assembly of allenes, organic halides and arylboronic acids has been reported in which Suzuki coupling of a Jt-allylpalladium complex with an orga-noboronic acid is utilized (Scheme 16.26) [31], Addition of phosphorus ligands to the reaction mixture greatly decreases either the product yields or E/Z ratios. The decrease in E/Z ratio may be explained based on the fact that donor ligands readily promote anti-syn rearrangement of a Jt-allylpalladium species via a cr-allylpalladium intermediate. 

A number of Suzuki reactions (see Scheme 10.9) have been conducted in ionic liquids using Pd(PPh3)4 as the catalyst at 30 °C [10], Although the catalyst is neutral, the ionic liquid-catalyst solution can be used repeatedly without a decrease in activity. In fact, the catalyst shows a significant increase in activity compared to when it is used in conventional organic solvents. Another attractive feature of the system is that NaHC03 and Na[XB(OH)2] (X = halide) by-products can be removed from the ionic liquid-catalyst phase by washing with water. 

The palladium-catalyzed coupling of boronic acids with aryl and alkenyl halides, the Suzuki reaction, is one of the most efficient C-C cross-coupling processes used in reactions on polymeric supports. These coupling reactions requires only gentle heating to 60-80 °C and the boronic acids used are nontoxic and stable towards air and water. The mild reaction conditions have made this reaction a powerful and widely used tool in the organic synthesis. When the Suzuki reaction is transferred to a solid support, the boronic add can be immobilized or used as a liquid reactant Carboni and Carreaux recently reported the preparation of the macroporous support that can be employed to efficiently immobilize and transform functionalized arylboronic adds (Scheme 3.12) [107, 246, 247]. 

In general terms Suzuki coupling refers to the reaction of organic halides with boronic acids and boronates (Scheme 6.8). These compounds are fairly stable to hydrolysis, so application of aqueous solvents [7-11] is quite straightforward. 

Zapf, A. Coupling of Aryl and Alkyl Halides With Organoboron Reagents (Suzuki Reaction). In Transition Metals for Organic Synthesis (2nd edn), Beller, M. Bolm, C. eds., 2004, 1, 211-229. Wiley-VCH Weinheim, Germany. (Review). 

BMIM]BF4 was applied to a Suzuki reaction. The active catalyst was a trico-ordinated [Pd(PPh3)2(Ar)][X] complex that formed after oxidative addition of aryl halide to [Pd(0)(PPh3)4] 211). The hydrophobic ionic liquid does not compete with the unsaturated organic substrate for the electrophilic active metal center. 

Historically, one of the most important limitations of the Suzuki-Miyaura reaction was the poor reactivity of organic chlorides, attributed to the strength of the C-Cl bond. Aryl chlorides are very attractive halides due to their low cost and wider diversity of available compounds. Prior to 1998, reports of effective palladium-catalyzed Suzuki reactions of aryl chlorides were limited to activated substrates, and generally employing very high temperatures. In that year. 

Reaction of (diisopropylamino)chloroboryl ethers of alkynols (57) with alkynyl-stannanes (58) in the presence of nickel catalysts has been reported to afford formal f/ms-alkynylboration products (60), which could undergo the Suzuki-Miyaura coupling with organic halides. The 2-borylalkenylnickel(II) complex (59) was isolated as an intermediate in a reaction of the chloroboryl ether (57) with 1 equiv. of a nickel(0)-phosphine complex and characterized by X-ray crystallography.61... 

S. Suzuki, Cross-Coupling Reactions of Organoboron Compounds with Organic Halides, in Metal-catalyzed Cross-coupling Reactions (F. Diederich, P. J. Stang, Eds.), Wiley-VCH, Weinheim, 1998, 49-89. 

Suzuki reaction Reaction of an organic halide with an organoboron reagent in the presence of a palladium catalyst (Section 26.2)... 

The Suzuki reaction is a palladium-catalyzed coupling of an organic halide (R X) with an organoborane (RBY2) to form a product (R-R ) with a new C-C bond. Pd(PPh3)4 is the typical palladium catalyst, and the reaction is carried out in the presence of a base such as NaOH or NaOCH2CH3. 

Suzuki reaction (Section 26.2) The palladium-catalyzed coupling of an organic halide (R X) with an organoborane (RBY2) to form a product R—R . 

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