Boron acid derivatives

The transition metal catalyzed cross coupling of an organohalide with a boronic acid derivative, the Suzuki-Miyaura coupling, has become one of the most popular ways of preparing biaryls.3 The reaction is very robust and can easily be scaled to provide multigrams of material.4... 

Diethylboryl)pyridines and (3-Aminophenyl)boronic Acid Derivatives... 

Fig. 4. Tetrameric 13 and trimeric 14, 15 macrocyclic structures obtained from (3-aminophenyl)boronic acid derivatives...

FuNn iONAL Group Tolerance of PdildbrO VIMes.HCI Catalyzed Suzuki Cross-Coupling Reactions of Aryl Chlorides with Phenyi.boronic Acid Derivatives... 

Boronic acid derivatives are able to form ring structures with other molecules having neighboring functional groups consisting of 1,2- or 1,3-diols, 1,2- or 1,3-hydroxy acids, 1,2- or 1,3-hydroxylamines, 1-2- or 1,3-hydroxyamide, 1,2- or 1,3-hydroxyoxime, as well as various... 

Typically, the boronic acid group is part of an aminophenyl boronic acid derivative, and this group has been used for bioconjugation and affinity chromatography purposes (Burnett et al., 1980 O Shannessy and Quarles, 1987). A common partner for a phenyl boronic acid group in bioconjugation is the salicylhydroxamic acid (SHA) group (Chapter 17, Section 3) (Reaction 59). 

The medicinal importance of 2-aryltryptamines led Chu and co-workers to develop an efficient route to these compounds (130) via a Pd-catalyzed cross-coupling of protected 2-bromotryptamines 128 with arylboronic acids 129 [137]. Several Suzuki conditions were explored and only a partial listing of the arylboronic acids is shown here. In addition, boronic acids derived from naphthalene, isoquinoline, and indole were successfully coupled with 128. The C-2 bromination of the protected tryptamines was conveniently performed using pyridinium hydrobromide perbromide (70-100%). 2-Phenyl-5-(and 7-)azaindoles have been prepared via a Suzuki coupling of the corresponding 2-iodoazaindoles [19]. 

Carbohydrate detection is important for applications such as glucose monitors these are arguably one of the most successful and relevant biosensors. An interesting fluorescence recovery-type saccharide sensor based on the reactivity of carbohydrates with boronic acids was reported in 2002 [36]. Specifically, modification of the cationic viologen-linked boronic acid derivative 40 to a zwitterionic species 41 upon covalent and reversible reaction of boronic acid with monosaccharides (Scheme 1) can cause the dissociation of the ion-pair in-... 

Attempts at preparing substituted cytosine 5-boronic acid derivatives 363 were unsuccessful, as it was found that these compounds underwent a very fast deboronation to produce 364 <1998J(P2)841>. 

Several pyrimidine boronic acid derivatives are now commercially available, and numerous other examples can be found in the literature, as their use in Suzuki and related cross-coupling chemistry is now well established . 

The reaction is initiated by addition of the amine 2 to the a keto acid 3, catalyzed by the vinyl boronic acid derivative 1. Use orbital interaction theoretical arguments to explain the following features of this synthesis ... 

Starting from 5,6-diaminouracils and boronic acid derivatives, some purine analogues were prepared, e.g. (60) (67AF607, 70CR(C)(27l)754). 

Reaction between 2-aminobenzamides and boronic acid derivatives give 1,2-dihydro-... 

The Stille coupling is closely related to the Suzuki coupling. The only difference is that a stannane is used instead of a boronic acid derivative, and that a base is not generally required. Additional functional groups tolerated in the reactants include hydroxyl, azide, nitro, oxirane, and carbamate groups, but neither primary aliphatic... 

Suzuki coupling chemistry of benzene boronic acid derivatives and haloben-zenes using a Pd(0) catalyst has also been employed for the synthesis of substituted PPPs as illustrated by the A-B type monomer 16 [67-73]. These initial syntheses were carried out under heterogeneous conditions at a basic pH as illustrated by Scheme 21. Such Suzuki coupling polymerizations are rather attractive alternatives as a wide variety of functional groups can be tolerated with minimal interference in the coupling scheme. 

The use of alkenyl boronic acid derivatives 50, which are readily prepared via hydroboration or bromoboration of alkynes, affords the corresponding p,y-unsaturated amino acids (e.g. 52-57) in a geometrically pure form [34], A variety of amines 48, including primary and secondary amines, anilines, amino alcohols and hydroxylamines can effectively participate in this process, while the alkenyl boronic acid can contain alkyl, aryl or bromo-substituents. Although the alkenyl amino acid side chain is introduced through the boronic acid component, the use of more substituted a-keto acids 49 allows the simultaneous incorporation of an additional a-substituent (e.g. 57). 

The one-step reaction among an amine, a carbonyl and a boronic acid derivative is a highly versatile multicomponent reaction that utilizes readily available compo-... 

Scheme 4.3 Iron as a structural and sensing element in 4.55. Fluoride binding to the boronic acid derived groups results in a lowering of the ferrocene-derived core s oxidation potential, allowing aerial oxidation of the Fe(II) centre to Fe (III) with concomitant colour change from orange to green.

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