A Convenient Synthesis of Novel Glycosyl Azetidines Under Mitsunobu Reaction Conditions

Abstract

A facile, simple, and high-yielding protocol for synthesis of novel glycosyl azetidines was developed from glycosyl β-amino alcohols via intramolecular cyclization under Mitsunobu reaction conditions.

GRAPHICAL ABSTRACT

Keywords:

• DIAD/PPh₃
• glycosyl amino alcohol
• glycosyl amino ester
• glycosyl azetidines
• Mitsunobu reaction

ACKNOWLEDGMENTS

We thank CISC, BHU, and CDRI, Lucknow, for spectroscopic data of synthesized molecules and Virendra Prasad for his scientific discussion. The Council of Scientific and Industrial Research, New Delhi, is gratefully acknowledged for financial support.

Notes

^a Diastereoselectivity of conjugate additions was determined by comparative signal in ¹H NMR spectrum of crude glycosyl β-amino ester (2–7), where InCl₃ or DBU/DABCO could not result in better selectivity and the configuration was determined by J _4,5 in ¹H NMR spectrum of corresponding alcohols.

^b Yield refers the isolated product. All intramolecular cyclization reactions were carried out in anhydrous THF for 12 h.

^c Intermolecular cyclization of compound 8 using PPh₃/DEAD results in comparatively poor yield of compound 14.

This article is dedicated to V.K.T.'s doctoral mentor, Dr. R. P. Tripathi, Senior Scientist at Central Drug Research Institute, Lucknow, India.