Protecting group enabled stereocontrolled approach for rare-sugars talose/gulose via dual-ruthenium catalysis.

Carbohydr Res

Carbohydrate Chemistry Research Laboratory (CCRL), Department of Chemistry, Malaviya National Institute of Technology (MNIT), Jaipur, 302017, India. Electronic address:

Published: January 2023


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Article Abstract

We herein report a convenient and highly stereocontrolled approach for rare and vital ᴅ-talo and ᴅ-gulo sugars directly from economical ᴅ-galactal through dual ruthenium-catalysis. The stereo-divergent strategy involves Ru(III)Cl-catalyzed Ferrier glycosylation of ᴅ-galactal to give 2,3-unsaturated ᴅ-galactopyranoside, further selective functionalization of C-4 and C-6 position with diverse protecting groups and dihydroxylation with Ru(VIII)O generated in situ providing access to talo/gulo isomers. The α-anomeric stereoselectivity and syn-diastereoselectivity in glycosylation-dihydroxylation steps have been predominantly achieved by judicious selection of stereoelectronically diverse protecting groups. The synthetic utility of the dual-ruthenium catalysis was demonstrated for efficiently assembling the ᴅ-talose and/or ᴅ-gulose sugars in natural products and bioactive scaffolds.

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http://dx.doi.org/10.1016/j.carres.2022.108705DOI Listing

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