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.
نویسندگان
چکیده
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.
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ورودعنوان ژورنال:
- Journal of the American Chemical Society
دوره 125 6 شماره
صفحات -
تاریخ انتشار 2003