Asymmetric boron-catalyzed reactions

Enantiomerically pure amino acids, amino alcohols, amines, alcohols, and epoxides play an increasingly important role as intermediates in the pharmaceutical industry and agrochemistry, where both a high degree of purity and large quantities of the compounds are required. The chemical industry has primarily relied upon established chemical methods for the synthesis of these intermediates, but is now turning more and more to enzymatic and biotechnological fermentation processes. For the industrial implementation of many transformations alternative methods are available. The advantages of the individual methods will be discussed herein and exemplified by syntheses of relevant compounds.

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“…[153] A review by Deloux and Srebnik provides a comprehensive overview of boranecatalyzed reactions. [154] …”

Section: Enantiomerically Pure Intermediatesmentioning

confidence: 99%

Industrial Methods for the Production of Optically Active Intermediates

Breuer¹,

Ditrich²,

Habicher³

et al. 2004

Angew Chem Int Ed

1,334

625

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“…Oxazaborolidines derived from chiral β-amino alcohols are regarded as important catalysts for the enantioselective reduction of C==O and C==N bonds (Corey & Helal, 1998;Deloux & Srebnik, 1993;Singh, 1992;Puigjaner et al, 1999), and for other enantioselective organic transformations (Wallbaum & Martens, 1992;Joshi et al, 1989). The 1,3,2-oxazaborolidine derived from the (S)-α,α-diphenyl prolinol, (Scheme), known as the Corey, Bakshi and Shibata (CBS) catalyst, (I), is the most efficient for the reduction of aromatic ketones (Corey et al, 1987;Mathre et al, 1991).…”

Section: Commentmentioning

confidence: 99%

“…The CBS reagent is reported to be extremely sensitive to air and moisture and difficult to purify. Therefore, it is usually prepared in situ, without characterization, and used as a reagent or catalyst in many enantioselective transformations (Corey & Helal, 1998;Deloux & Srebnik, 1993;Singh, 1992;Yadav et al, 2000;Garrett et al, 2002). Pure CBS oxazaborolidine was isolated and characterized by Corey and coworkers (Corey et al, 1987), who prepared the reagent by refluxing the corresponding chiral amino alcohol with an excess of borane-tetrahydrofuran (THF) complex under a closed argon-borane atmosphere system.…”

Section: Commentmentioning

confidence: 99%

A 1,3,2-oxazaborolidine dimer derived from (S)-α,α-diphenylprolinol

et al. 2004

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The reaction of (S)‐α,α‐diphenylprolinol with an excess of borane–tetrahydrofuran complex yields a stable crystalline material with the composition C34H38B2N2O2, which features a borane adduct of a spirocyclic structure with two oxazaborolidine rings joined by a central tetrahedral B atom. This dimeric oxazaborolidine complex, viz. 3,3,3′,3′‐tetraphenyl‐1,1′‐spirobi(3a,4,5,6‐tetrahydro‐3H‐pyrrolo[1,2‐c][1,3,2]oxazaborole)–7‐borane, is the dominant product under various reaction conditions; its crystal structure is consistent with 11B, 1H and 13C NMR and IR analyses.

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“…Moreover, biological activity of oxazaborolidines has also been investigated and some oxazaborolidines have been reported to show antibacterial activity against Streptococcus mutans [17]. The importance of oxazaborolidines in modern organic chemistry is indisputable and the large interest in this area resulted in several comprehensive reviews [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

The B–H–B bridging interaction in B-substituted oxazaborolidine–borane complexes: a theoretical study

et al. 2012

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Ten oxazaborolidine-borane complexes, nine among them boron-substituted (B-R, R=CH 3 , CF 3 , and OCH 3 ), are carefully analysed using quantum-chemistry methods to determine their equilibrium geometries and the corresponding oxazaborolidine-borane interaction energies. It is observed that in all B-trifluoromethyl substituted oxazaborolidine-borane complexes and in one B-methyl substituted complex the B-H-B bond is formed and the interaction energies are 1.5-2.5 times as large as in other investigated complexes. We believe that the presented results may be helpful in experimental recognition of oxazaborolidine-borane complexes which may appear, inter alia, as reaction intermediates.keywords B-substituted oxazaborolidine-borane complexes Á B-H-B bond Á Ab initio calculations Á Density functional theory calculations Á Intermolecular interaction energy

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Asymmetric boron-catalyzed reactions

Cited by 470 publications

References 26 publications

Industrial Methods for the Production of Optically Active Intermediates

Industrial Methods for the Production of Optically Active Intermediates

A 1,3,2-oxazaborolidine dimer derived from (S)-α,α-diphenylprolinol

The B–H–B bridging interaction in B-substituted oxazaborolidine–borane complexes: a theoretical study

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