284042-83-7Relevant academic research and scientific papers
The cohalogenation of 1-N-vinylpyrimidinediones: A new approach to nucleoside analogs
Baret, Nathalie,Dulcere, Jean-Pierre,Rodriguez, Jean,Pons, Jean-Marc,Faure, Robert
, p. 1507 - 1516 (2007/10/03)
A new approach to the synthesis of nucleoside analogs has been developed, which involves initial chemo- and regioselective cohalogenation of 1-N-vinylpyrimidinediones 10a,b using N-bromosuccinimide in the presence of variously substituted propargylic alcohols. Radical carbocyclization of the resulting β-bromo propargylic ethers 17-22 then leads to 3- methylenetetrahydrofurans 23-26. In such cyclizations, different reactivities have been observed for diastereomers 22a,b obtained by cohalogenation with (R)-1-benzyloxybut-3-yn-2-ol; although the expected anti 3- methylenetetrahydrofurans 27a,b were obtained, the syn diastereomers 28a,b were only the minor constituents of a mixture in which bicyclonucleosides 29a,b were the major components. The formation of 29a,b results from a 1,6- hydrogen transfer followed by cyclization, which might be favored by a CH-π interaction in radical intermediate syn II.
