Catalyzed Acetal Reduction with BH Boranes—1‐O‐Alkyl(aryl)alditols, Anhydroalditols, and 1‐O‐Alditylalditols from O‐Glycopyranosides

Köster, Roland; Penadés‐Ullate, Soledad; Dahlhoff, W. V.

doi:10.1002/anie.198505191

Cited by 11 publications

(3 citation statements)

References 6 publications

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“…Only a few reports have been published so far on the anomerization [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ] and attachment of nucleophiles at C1 [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] via the endocyclic cleavage of glycosides. To the best of our knowledge, the side reaction described here is the first example of the endocyclic cleavage of methyl α- D -allopyranoside derivatives with PhBCl 2 /Et 3 SiH.…”

Section: Introductionmentioning

confidence: 99%

Ring Cleavage Reactions of Methyl α-D-Allopyranoside Derivatives with Phenylboron Dichloride and Triethylsilane

et al. 2011

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In the course of our studies on the regioselective carbon-oxygen bond cleavage of the benzylidene acetal group of hexopyranosides with a reducing agent, we found that a combination of a Lewis acid and a reducing agent triggered a ring-opening reaction of the pyranose ring of methyl α-D-allopyranosides. The formation of an acyclic boronate ester by the attachment of a hydride ion at C-1 indicated that the unexpected endocyclic cleavage of the bond between the anomeric carbon atom and the pyranose ring oxygen atom proceeded via an oxacarbenium ion intermediate produced by the chelation between O5/O6 of the pyranoside and the Lewis acid, followed by nucleophile substitution with a hydride ion at C1.

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Section: Introductionmentioning

confidence: 99%

Ring Cleavage Reactions of Methyl α-D-Allopyranoside Derivatives with Phenylboron Dichloride and Triethylsilane

et al. 2011

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“…Despite their propensity to react with π-bonds, HBpin and HBcat are not yet known as reagents to reductively deoxygenate sp 3 C–O bonds . In contrast, silanes can be activated by numerous catalysts to achieve this outcome, as we − and others − have achieved selective C–O bond reduction in multifunctional compounds with the metal-free catalyst tris(pentafluorophenyl)borane (B(C 6 F 5 ) 3 ).…”

mentioning

confidence: 99%

“…7−10 Despite their propensity to react with π-bonds, HBpin and HBcat are not yet known as reagents to reductively deoxygenate sp 3 C−O bonds. 11 In contrast, silanes can be activated by numerous catalysts to achieve this outcome, 12 as we 13−18 and others 19−26 have achieved selective C−O bond reduction in multifunctional compounds with the metal-free catalyst tris(pentafluorophenyl)borane (B(C 6 F 5 ) 3 ). As elucidated by Piers 27 and Yamamoto, 28 B(C 6 F 5 ) 3 heterolytically activates the hydrosilane through a transient borane-silane adduct ((C 6 F 5 ) 3 B--H−SiR 3 ).…”

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confidence: 99%

Boron-Catalyzed Site-Selective Reduction of Carbohydrate Derivatives with Catecholborane

2018

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Catalytic sp3 C–O bond cleavage using B(C6F5)3/HBcat is reported. This method is first demonstrated on simple ethers and silyl protected alcohols, which exhibit reactivity parallel to the known B(C6F5)3/HSiR3 system. In more complex carbohydrate derivatives, however, unique selectivities that are not possible with hydrosilane reductants have been achieved, including regioselective cyclizations. Preliminary computational studies suggest that diboryl oxonium ions are disfavored and that four-coordinate boronium ions may contribute to selectivity.

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Selective C−O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers’ Borane Generated In Situ

2017

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Described herein is the selective reduction of sugars with hydrosilanes catalyzed by using Piers’ borane [(C6F5)2BH] generated in situ. The hydrosilylative C−O bond cleavage of silyl‐protected mono‐ and disaccharides in the presence of a (C6F5)2BH catalyst, generated in situ from (C6F5)2BOH, takes place with excellent chemo‐ and regioselectivities to provide a range of polyols. A study of the substituent effects of sugars on the catalytic activity and selectivity revealed that the steric environment around the anomeric carbon (C1) is crucial.

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Catalyzed Acetal Reduction with BH Boranes—1‐O‐Alkyl(aryl)alditols, Anhydroalditols, and 1‐O‐Alditylalditols from O‐Glycopyranosides

Cited by 11 publications

References 6 publications

Ring Cleavage Reactions of Methyl α-D-Allopyranoside Derivatives with Phenylboron Dichloride and Triethylsilane

Ring Cleavage Reactions of Methyl α-D-Allopyranoside Derivatives with Phenylboron Dichloride and Triethylsilane

Boron-Catalyzed Site-Selective Reduction of Carbohydrate Derivatives with Catecholborane

Selective C−O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers’ Borane Generated In Situ

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