Collect. Czech. Chem. Commun. 2004, 69, 1843-1876

2-Haloethyl 1-Thioglycosides as New Tools in Glycoside Syntheses. Part 1: Preparation, Characteristics, General Reactions

Andreas Krüger, Jutta Pyplo-Schnieders, Hartmut Redlich* and Pär Winkelmann

Organisch-Chemisches Institut der WWU Münster, Corrensstrasse 40, 48149 Münster, Germany


2-Haloethyl 1-thioglycosides are excellent leaving groups when the 2-haloethyl function is activated with silver salts or Lewis acids. These thioglycosides can be synthesized on the original Černý route or for better compatibility with the needs of a more complex glycoside synthesis, in stepwise procedures via 2-(2-tetrahydropyran-2-yloxy)ethyl glycosides or trityl 1-thioglycosides. The initial step in glycosidation reaction presumably proceeds via a thiiranium ion, which is responsible for their increased reactivity compared with normal thioethers as leaving groups in glycoside syntheses. Basic features of this new system with respect to reactivity and selectivity in disaccharide syntheses are described.

Keywords: Glycosides; Thioglycosides; Carbohydrates; Disaccharides; Glycosidation; Protecting groups; Leaving groups.

References: 30 live references.