Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400 076, India E-mail: suvarn@chem.iitb.ac.in Manuscript received online 20 November 2019, revised and accepted 21 December 2019 Herein we report assembly of the appropriately protected trisaccharide repeating unit of Cobetia pacifica KMM 3878 O-sulfated polysaccharide. Our synthesis involves 3,4-O-pyruvilated galactose as the key building block which acts as a donor as well as acceptor in the construction of trisaccharide. We obtained the R isomer as a major stereoisomer in the pyruvilation reaction. The glycosylations proceeded with high stereo and regioselectivity.
