Chemical Access to d -Sarmentose Units Enables the Total Synthesis of Cardenolide Monoglycoside N-1 from Nerium oleander

DOI:10.1021/acs.joc.7b00210 URL: http://www.sciencedirect.com/science/article/pii/S0926337317301832 Filiació URV: SI ; Herein we present a chemical approach for the ready preparation of d-sarmentosyl donors enabling the first total synthesis and structure validation of cardenolide N-1, a challenging 2,6-dideoxy-3-O-methyl-¿-d-xylo-hexopyranoside extracted from Nerium oleander twigs that displays anti-inflammatory properties and cell growth inhibitory activity against tumor cells. The strategy highlights the synthetic value of the sequential methodology developed in our group for the synthesis of 2-deoxyglycosides. Key steps include Wittig-Horner olefination of a d-xylofuranose precursor, [I+]-induced 6-endo cyclization, and 1,2-trans stereoselective glycosylation.