Suzuki coupling scope

We have broadened the scope of this reverse addition protocol to prepare a variety of boronic acids bearing different functional groups for use in Suzuki coupling reactions. The yield and quality of the boronic acid prepared by this reverse addition protocol is usually better than the sequential approach. The boronic acids can be used without further purification (formation of pinacols) in Suzuki coupling reactions. 

Organosilanes are stable and easily prepared compounds with low toxicity. With the many improvements in the reaction conditions that have been reported, the Hiyama Coupling has become an interesting alternative to the Suzuki Coupling that offers a comparable scope of conversions. On the other hand, the broad commercial availability of boronic acids and boronates currently makes the Suzuki Coupling the more convenient choice. 

The Suzuki Coupling, which is the palladium-catalysed cross coupling between organoboronic acid and halides. Recent catalyst and methods developments have broadened the possible applications enormously, so that the scope of the reaction partners is not restricted to aryls, but includes alkyls, alkenyls and alkynyls. Potassium trifluoroborates and organoboranes or boronate esters may be used in place of boronic acids. Some pseudohalides (for example triflates) may also be used as coupling partners. 

The scope and limitations of Pd(0)-mediated coupling reactions between aromatic halides linked to a polystyrene resin and boronic acid derivatives (Suzuki coupling) or arylstannanes (Stille coupling) have been reported. For all the reactions, the conditions were optimized and evaluated with various reagents. In most cases, products were obtained in excellent yields upon cleavage from the solid support (Eq. (63)) [101]. 

Suzuki couplings. Pd-catalyzed reactions of B-allyl borate complex derived from 6-methoxy-9-borabicyclo[3.3.1]nonane with aryl triflates give allylarenes. This technique broadens the scope of the Suzuki coupling to allow transfer of Me, TMSCHj, and alkynyl groups which has eluded conventional manipulations. 

The suitability of the homogeneous aqueous catalysts and thus the scope of application in general will be extended in commercial or pilot-plant operation to other central atoms and reactions such as Heck reactions and other carbonylations (with Pd), hydrogenations (Pd, Pt, Rh, Ir), formation of water-soluble polymers (Pd), vinylations, metathesis conversions (Ru), Suzuki couplings, etc. (cf. Section 6.6). 

Table 4.6 Substrate scope of Suzuki coupling reaction using St. Andrews ligands.

Ligand 19 is water soluble, and has been employed in Suzuki coupling reactions conducted in aqueous media. Ligand 17 provides optimal results in Suzuki coupling reactions of aryl tosylates and aryl benzenesulfonates. Ligand 16 is thought to have the greatest substrate scope of the Buchwald biaryl-phosphine derivatives, and is widely used in... 

The scope of the Suzuki cross-coupling reaction has been further increased by the utilization of novel boron derivatives. The synthesis of these coupling precursors has also been simplified as they are accessible from aromatic halides by means of a palladium-catalyzed procedure, which is more tolerant to functional groups than the original lithia-tion protocol. Examples of aromatic boron species are shown in Figure 12.3. A detailed account on boron species employed in Suzuki couplings has recently been published [120],... 

The scope of Suzuki-Miyaura reactions is extremely broad, covering practically all types of organic residues. The cross-coupling of arylboronic acids with aryl halides or triflates is the most... 

Anionic complexes of boron (boronates, borinates, etc.) have been introduced as convenient reagents in cross-coupling reactions of broad scope, particularly interesting for the transfer of alkynyl and primary alkyl residues, which cannot be accomplished using the standard protocols of the Suzuki-Miyaura reaction. Readily available Ph4BNa can be used as a convenient reagent for phenylation in place of the much more expensive PhB(OH)2, and all four phenyl groups can be utilized when the reaction is carried out with a phosphine-free catalyst in aqueous solutions.244... 

Figure 3.56. Scope of Pd/63-catalyzed as5mmetric Suzuki cross-coupling of naphthyl bromides with arylboronic acids.

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