A greener and simple catalytic system is developed for the synthesis of biologically important 3,3′-Bisindolyl(methanes) (BIMs) using C1 and C2 alcohols as carbon source for the bridging methylene group. The...

Herein, we report a concise synthetic approach for the first total synthesis of a pentasaccharide repeating unit of Acinetobacter baumannii K11 capsular polysaccharides containing a rare sugar 6-deoxy-L-talose. The pentasaccharide was synthesized in a convergent manner using a [3 + 2] block glycosylation strategy. During this synthetic strive, we used a 2,2,2trichloroethoxycarbonyl (Troc)-protected monosaccharide unit to achieve a high yield during the glycosylation to synthesize a trisaccharide, and chemoselective deprotection of the Troc group from the trisaccharide was carried out under a mild, pH-neutral condition, keeping the O-glycosidic bond, azido, and acid/base sensitive group intact. A thiotolylglycoside disaccharide donor containing 6-deoxy-L-talose was synthesized for the first time by the armed-disarmed glycosylation method between two thiotolylglycosides.