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SN2-Type Glycosylation with Unprotected Pyranoses

preprint
submitted on 27.11.2019, 09:00 and posted on 03.12.2019, 11:29 by Hironori Takeuchi, Yusuke Fujimori, Hiromitsu Shibayama, Masaru Nagaishi, Yoshihiro Ueda, Tomoyuki Yoshimura, Takahiro Sasamori, Norihiro Tokitoh, Takumi Furuta, Takeo Kawabata

An SN2 mechanism was proposed for highly stereoselective glycosylation of benzoic acid with unprotected α-D-glucose under Mitsunobu conditions in dioxane, while an SN1 mechanism seems to be responsible for non-stereoselective glycosylation in DMF. The SN2-type glycosylation can be applicable to various unprotected pyranoses as glycosyl donors and a wide range of carboxylic acids, phenols, and imides as glycosyl acceptors, retaining its high stereoselectivity (34 examples). Glycosylation of a carboxylic acid with unprotected α-D-mannose proceeded also in an SN2 manner to directly afford a usually less accessible 1,2-cis-mannoside. An extremely short-step total synthesis of a middle molecule (1874 Da) natural glycoside with antitumor activity, coriariin A, was achieved via a double SN2 glycosylation strategy with two molecules of unprotected α-D-glucose.

Funding

JSPS KAKENHI JP26221301

JSPS KAKENHI JP15K18827

JSPS KAKENHI JP23105008

JSPS KAKENHI JP16H01148

Naito Foundation

History

Email Address of Submitting Author

kawabata@scl.kyoto-u.ac.jp

Institution

Kyoto University

Country

Japan

ORCID For Submitting Author

0000-0002-9959-0420

Declaration of Conflict of Interest

The authors declare no competing financial interest.

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