University of Missouri - Saint Louis

The Graduate School

Announcement

An oral examination in defense of the dissertation for the degree

Doctor of Philosophy

James T. Smoot
B.A. in Chemistry, May 1994, Southern Illinois University Carbondale.
M.S. in Chemistry, May 2004, University of Missouri-St. Louis.

Development of the Inverse Armed-Disarmed Strategy for Oligosaccharide Synthesis

Abstract

A number of synthetic strategies enabling the convenient assembly of oligosaccharides exist. One of the most efficient procedures, Fraser-Reid’s armed-disarmed glycosylation strategy, is based on the chemoselectivity principle, in which an armed glycosyl donor is activated over a disarmed acceptor to afford a 1,2-cis-linked disaccharide. The armed-disarmed glycosylation strategy simplifies the synthesis of cis-trans or cis-cis-linked oligosaccharides. It is not, however, applicable for the synthesis of trans-cis, or trans-trans-linked trisaccharides. To address this problem, we have developed a glycosylation strategy for the preparation of these glycosylation patterns without protecting group manipulations between glycosylation steps.

The development of the Armed-Disarmed Strategy for S-thiazolyl (STaz) glycosides, when combined with the 2-picolyl protective group, have allowed for the development of the Inverse Armed-Disarmed strategy. Here we report the application of STaz-glycosides as glycosyl donors in our attempts to obtain cis-trans, trans-trans, cis-cis, and trans-cis glycosylation patterns. To synthesize these trisaccharides, we utilized the chemoselectivity principle by the activation of one building block over another, which has been deactivated by a disarming moiety. The resulting disarmed disaccharide was then subsequently activated by a stronger promoter to yield the trisaccharide.

Defense of Dissertation Committee