Highly reactive 2-deoxy-2-iodo-D-allo and D-gulo pyranosyl sulfoxide donors

Highly reactive 2-deoxy-2-iodo-D-allo and D-gulo pyranosyl sulfoxide donors

ensure b-stereoselective glycosylations with steroidal algycones

J. Mestre, D. Collado, D. Benito-Alifonso, M.A. Rodriguez, M.I. Matheu, Y. Díaz, S. Castillón, O. Boutureira.
RSC Adv. 2018, 8, 30076-30079.

The preparation of well-defined D-xylo and D-ribo glycosides represents a synthetic challenge due to the limited configurational availability of starting materials and the laborious synthesis of homogeneous 2-deoxy-β-glycosidic linkages, in particular that of the sugar-steroid motif, which represents the “stereoselective determining step” of the overall synthesis. Herein we describe the use of 2-deoxy-2-iodo-glycopyranosyl sulfoxides accessible from widely available D-xylose and D-ribose monosaccharides as privileged glycosyl donors that permit activation at very low temperature. This ensures a precise kinetic control for a complete 1,2-trans stereoselective glycosylation of particularly challenging steroidal aglycones.

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