title: A new reaction manifold for the Barton radical intermediates: synthesis of N-heterocyclic furanosides and pyranosides via the formation of the C(1)-C(2) bond.
abstract: The first radical intermediate in the thiourethane-mediated deoxygenation of an alcohol (Barton-McCombie reaction) can participate in an exo-hex-5-enyl- or exo-hept-6-enyl-type radical cyclization when a suitable radical acceptor (e.g., alpha,beta-unsaturated ester, oxime ether, or hydrazone) is appropriately placed. Carbohydrate-derived imidazolyl and triazolyl thiourethanes with such acceptors, upon addition to excess of a good hydride donor (reverse addition), undergo efficient cyclization reactions to give N-heterocyclic furanosides, and, surprisingly even N-pyranosides. Depending on the acceptor, glycosides with either a C(2)()-amino or a C(2)()-carbon substituent are formed.
authors.affiliation: Department of Chemistry, 100 West 18th Avenue, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Jong Uk
authors.initials: JU
authors.lastname: Rhee
authors.forename: Brian I
authors.initials: BI
authors.lastname: Bliss
authors.forename: T V
authors.initials: TV
authors.lastname: RajanBabu