Yadav Y, Tyagi R, Yadav K, Tiwari G, Sagar R. Reinvestigation of SnCl
4 catalyzed efficient synthesis of 2,3-unsaturated glycopyranosides.
Carbohydr Res 2023;
534:108989. [PMID:
38016255 DOI:
10.1016/j.carres.2023.108989]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 11/30/2023]
Abstract
The Ferrier rearrangement is a powerful tool to prepare 2,3-unsaturated glycopyranosides. We have reinvestigated SnCl4 catalyzed Ferrier rearrangements through direct allylic substitution of the hydroxyl group at the C-3 position of glycals, resulting in the formation of stereoselective 2,3-unsaturated glycosides at 0 °C. The catalytic amount of SnCl4 (0.1 equiv.) was successfully used to promote this transformation on 3,4,6-tri-O-acetyl-D-glucal, 3,4,6-tri-O-acetyl-D-galactal and 3,4-di-O-acetyl-D-arabinal using various nucleophiles viz alcohols, azide and thiols to form a variety of 2,3-unsaturated glycopyranosides (pseudoglycals). This straightforward process is notable for its strong anomeric selectivity, excellent yields and shorter reaction time.
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