Palladium organoborons

Palladium-catalyzed cross-coupling with organoboron compounds... 

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. 

In 1975, Heck described the first non-catalytic example of this reaction, nsing organoboronic acids as precursors and stoichiometric amounts of palladium acetate... 

Scheme 8.14. Palladium-Catalyzed Cross Coupling of Organoboron Reagents...

The regioselectivity of palladium-catalyzed additions of organoboronic acids to unsymmetrical alkynes is strongly dependent on steric and electronic effects (Scheme 12).62 Multi-component reaction has been reported for the synthesis of tetrasubstituted alkenes.58 The aryl group from an aryl iodide is generally added to the less hindered... 

Grigg developed several palladium-catalyzed tandem cyclization-anion capture processes, and these include organoboron anion transfer agents [112, 164, 206]. Two examples of this methodology are shown. 

The application of in situ-generated (alkoxy)palladium(II) species (Scheme 14.23) can be extended to reactions of a-carbonates with organoboron compounds. Crosscouplings of allenes 108 with aryl (or alkenyl) boron acids or their esters catalyzed by a palladium(O) complex afforded the 2-aryl(alkenyl)-l,3-butadienes 109 in excellent yields (Scheme 14.24) [53], The coupling reactions of 9-BBN-derived intermediates such as ester 111 can be accelerated by applying K3P04 as additive (Eq. 14.15). 

Palladium- and copper-catalysed cross-coupling of organotellurium dichlorides with organostannanes and organoboronic acids... 

Jang, S.-B, Polymer-Bound Palladium-Catalysed Cross-coupling of Organoboron Compounds with Organic Halides and Organic Triflates, Tetrahedron Lett. 1997, 38, 1793-1796. 

Miyaura, N. Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds, Chem. Rev. 1995, 95, 2457-2483. 

Palladium catalysts have been found which are effective in the Suzuki coupling reaction of arylboronic acids with aryl chlorides carrying electron-withdrawing groups.73 Biaryls may also be synthesized by cross-coupling of arylboronic acids with arenediazonium salts.74,75 There has been a report of the polymer-bound palladium-catalysed Suzuki coupling of aryl triflates with organoboron compounds.76 Arylbor-onates may themselves be synthesized by the palladium-catalysed reactions of... 

Suzuki reaction A palladium catalyzed reaction that results in the formation of new carbon to carbon bonds by reacting an organohalide or organotriflate with an organoboronic acid. 

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