Highly reactive 2-deoxy-2-iodo-d- allo and d- gulo pyranosyl sulfoxide donors ensure β-stereoselective glycosylations with steroidal aglycones

• Published in: RSC advances Vol. 8; no. 53; pp. 30076 - 30079
• Main Authors: Mestre, Jordi, Collado, David, Benito-Alifonso, David, Rodríguez, Miguel A, Matheu, M Isabel, Díaz, Yolanda, Castillón, Sergio, Boutureira, Omar
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 01-01-2018; The Royal Society of Chemistry
• Subjects: Chemistry; Monosaccharides; Ribose; Stereoselectivity; Sulfoxides; Synthesis; Xylose
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c8ra06619a

The preparation of well-defined d-
and d-
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-
stereoselective glycosylation of particularly challenging steroidal aglycones.