{Reference Type}: Journal Article
{Title}: Convergent total synthesis of Cryptococcus neoformans serotype B capsule repeating motif.
{Author}: Crawford CJ;Oscarson S;
{Journal}: Carbohydr Res
{Volume}: 497
{Issue}: 0
{Year}: Nov 2020
{Factor}: 2.975
{DOI}: 10.1016/j.carres.2020.108150
{Abstract}: Cryptococcus neoformans is an opportunistic fungal pathogen, which is a frequent cause of a life-threatening meningitis in immunocompromised individuals. We report the first total synthesis of the serotype B heptasaccharide repeating motif. The use of di- and trisaccharide building blocks enabled a concise convergent synthesis of the protected 6-O-acetylated repeating motif in three steps. Glycosylations gave total 1,2-trans selectivity, despite the absence of a neighboring participating group. Using our recently disclosed catalyst pre-tuning strategy global deprotection gave the desired 6-O-acetylated heptasaccharide with no saturation by-products, overall in four steps 31% yield. The serotype B glucuronoxylomannan (GXM) glycans accessed in this study will increase the structurally diversity of our GXM microarray, allowing further steps towards the development of semi-synthetic vaccines against cryptococcal infections.