Model Compounds for the Photoactivation of Glycosyl Donors

Nature exhibits complex arrays of carbohydrates in many different forms. Carbohydrate chemists still face many challenges in the synthesis of these complex substrates. This project aims to offer carbohydrate chemists a novel way of activating the anomeric position of a sugar by light to promote glycosylation. This involved photolyzing model pyran compounds, in the presence of various photosensitizers, to induce an intramolecular cyclization. This cyclization leads to the generation of an oxonium intermediate that may alkylate other nucleophiles, which should be analogous to a glycosylation reaction. It was determined that a moiety with an internal sensitizer could photochemically exchange a tetrahydropyran at 300 nm. It was also determined that 6- methylhex-5-en-1-ol-THP ether, 6-methylhept-5-en-2-ol-THP ether, and 3-methylbut-2- en-1-ol-THP ether will transfer a pyran to a nucleophile in the presence of stoichiometric tetrachloroquinone at 350 nm. THP-ethers such as 6-methylhex-5-en-1-ol-THP ether and 3-methylbut-2-en-1-ol-THP will transfer a pyran to a nucleophile in presence of catalytic dicyanobenzene at 350 nm. α-Terpineol-THP Ether will transfer a pyran at 419 nm, using catalytic amounts of dichloroquinone. A fast and efficient way to photochemically install a THP group on an alcohol was also discovered. The synthesis, characterization, and mechanistic principles of these compounds are discussed as potential candidates for glycosyl activation.

Grantor dc:publisher

Wake Forest University

Year dc:date.issued

2008

Author dc:creator

• Oates, Richard

• photoactivation

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10339/14910

OAI identifier oai:identifier

oai:wakespace.lib.wfu.edu:10339/14910