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

doi:10.3390/molecules161210303

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Molecules 2011, 16(12), 10303-10313; doi:10.3390/molecules161210303

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

Masaru Kojima * , Yutaka Nakamura, Yuusuke Ito and Seiji Takeuchi

Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 956-8603, Japan

* Author to whom correspondence should be addressed.

Received: 31 October 2011; in revised form: 25 November 2011 / Accepted: 5 December 2011 / Published: 13 December 2011

(This article belongs to the Special Issue Stereoselective Synthesis)

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Abstract: 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.

Keywords: methyl α-D-allopyranoside; endocyclic cleavage; phenylboron dichloride; triethylsilane

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Cite This Article

MDPI and ACS Style

Kojima, M.; Nakamura, Y.; Ito, Y.; Takeuchi, S. Ring Cleavage Reactions of Methyl α-D-Allopyranoside Derivatives with Phenylboron Dichloride and Triethylsilane. Molecules 2011, 16, 10303-10313.

AMA Style

Kojima M, Nakamura Y, Ito Y, Takeuchi S. Ring Cleavage Reactions of Methyl α-D-Allopyranoside Derivatives with Phenylboron Dichloride and Triethylsilane. Molecules. 2011; 16(12):10303-10313.

Chicago/Turabian Style

Kojima, Masaru; Nakamura, Yutaka; Ito, Yuusuke; Takeuchi, Seiji. 2011. "Ring Cleavage Reactions of Methyl α-D-Allopyranoside Derivatives with Phenylboron Dichloride and Triethylsilane." Molecules 16, no. 12: 10303-10313.

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