Suzuki reaction synthetic utility

Hartwig-Buchwald, Suzuki, and Stille type cross-coupling reactions with key intermediate 46 led to a wide range of substituted sulfoximines such as 47-49 [37]. In order to demonstrate the synthetic utility of the resulting products, pseudo tripeptide 50 was prepared from a related intermediate. 

Many Suzuki reactions have been applied in aromatic-heteroaromatic and heteroaromatic-heteroaromatic couplings by virtue of their synthetic utility in the pharmaceutical industry. This section deals with such reactions. 

Suzuki, A., and Dhillon, R. S. Selective Hydroboration and Synthetic Utility of Organoboranes Szele, J., Zollinger, H. Azo Coupling Reactions Structures and Mechanisms. 112, 1-66 (1983). 

Salen ligands have found utility in a number of synthetically useful reactions. Pyridine modified salicylaldehydes 212 have been prepared by the hydrolysis of 211, the product of a Suzuki reaction of 209 with 210 [75]... 

Functionalized alkenyl diamino- and dialkoxyboranes have been produced regio-and stereoselectively through addition of carbon- or heteroatomgenerated from bromotrichloromethane, thiols, phosphines and tributyltin hydride) to ethynylbis(diisopropylamino)boranes. The synthetic utility of these reactions was illustrated by the preparation of stereodefmed (Z)- or ( )-alkenylboronic esters via palladium-catalyzed crossStille reaction and a Suzuki coupling under basic conditions can be further conducted (Scheme 9.14) [33]. 

The development of reaction conditions for the participation of aryl triflates in the Suzuki reaction (725,747,742) expands the synthetic utility of tfiis reaction since triflates are readily obtained from phenols (745). Due to their inherent base sensitivity and thermally lability, mild reaction conditions have been developed for the cross-coupling reaction of arylboronic acids with triflates. High yields are obtained using weak bases, such as powdered K3PO4 or Na2C03, suspended in non-aqueous polar solvents (THF, dioxane) (725,742). Alkali metal halides are added to promote the cross-coupling and/or to prevent the premature catalyst decomposition (725,747). The utilization of more efficient catalysts such as PdCl2(dppf) also permit this reaction to proceed at lower temperatures (725). 

The synthetic utility of the Suzuki reaction for polymer synthesis has also been demonstrated through the synthesis of polymers with Frechet-type dendritic substituent groups (247) and through progress made toward the preparation of large oligophenylene cycles (248),... 

Chemists working to develop new bioactive compounds try to be alert for new stable heterocycle platforms, but they can easily overlook some of the more, shall we say, exotic ones. When one thinks about the utility of boron in heterocyclic chemistry, the Suzuki cross-coupling reaction typically first comes to mind. In this valuable synthetic reaction <95CRV2457>, a boronic acid group is discarded under basic conditions during a Pd-catalyzed C-C bond formation. There are exceptions, of course, but few chemists appreciate that boron is an element that can be valuable to retain in a molecule so that its unique properties can be utilized. 

Workers at Sphinx [24] have published a synthetic route to a series ofhighly functionalized biphenyl compounds. The key reactions in this sequence are the biaiyl Stille and/or Suzuki couplings to form the biphenyl nucleus and the use of Mitsunobu chemistry to attach the variable side chains (Fig. 2). The illustrated route utilizes a solution-based diaryl coupling followed by on-resin Mitsunobu reactions. Although the diaiyl coupling proceeds on solid phase, this group s desire to maximize resin loading prompted them to implement the former route. 

The use of aryl triflates or other sulfonates in the amine arylation reaction is highly desirable from a synthetic standpoint since a large variety of phenols are easily accessed and derivatized. Aryl and vinyl triflates have enjoyed great utility in other Pd-catalyzed transformations such as the Stille [77] and Suzuki [78] couplings, and the Heck [79] reaction. 

Spiro-linked compounds containing heterocyclic units have been prepared for many apphcations. In general, there are two synthetic pathways to build up heterocyclic spiro compounds. On the one hand, cross-coupling reactions like the Negishi, Kharash, Stille, Suzuki, or Sonogashira coupling reaction can be utilized to connect the heterocychc subunit with the central spiro core [118]. On the other hand, the heterocycle can be built up from spiro precursors containing heteroatoms. 

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