Transformation of glycals to 2,3-di-substituted-3-dexoy-glycals were achieved by sequential C2 alkenylation of pseudoglycals followed by capture of nucleophiles at C3 position. Anomeric linked N-(glycosyloxy) acetamides group assisted innate C2-H activation of pseudoglycals under palladium catalysis is achieved. The synthesized C2 alkenylated products were further attacked by thio/amino nucleophiles at C3 position under basic conditions in stereo-selective fashion to generate 2,3-branched glycals with the elimination of directing groups and translocation of double bond. Different control experiments were conducted to establish the role of directing groups in C-H functionalization of pseudoglycals and reason for selectivity.
Keywords: 2,3-di-substituted-3-dexoy-glycals; C−H activation; amino sugar; directing group; pseudoglycals; thiosugar.
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