Glycosyl tetrazoles as glycosyl donors for the synthesis of 2-deoxy glycosides

Abstract

2-Deoxy oligosaccharides form a major component of biologically active aureolic acid and angucycline antibiotics. The instability of 2-deoxy oligosaccharides and difficulty in controlling their stereoselectivity of coupling reactions is primarily due to the lack of a C-2 substituent. This thesis introduces a new method of 2-deoxy glycosylation. Condensation of 2-deoxy sugars with 1H-tetrazole and di-t-butylphosphoramidite produces N2 and N1 isomer of the tetrazole adduct. Glycosylations using either isomers as glycosyl donors were examined under different glycosylation conditions. Repetition of the coupling protocol enables the assembly of a trisaccharide model system of PI-080. Synthesis of this trisaccharide demonstrates the synthetic utility of glycosyl tetrazoles as potential glycosyl donors in the synthesis of oligosaccharides.