Additive Pummerer Reaction of 3,5-<i>O</i>-(Di-<i>tert</i>-butyl)silylene-4-thiofuranoid Glycal: A High-Yield and β-Selective Entry to 4′-Thioribonucleosides
作者:Kazuhiro Haraguchi、Hiromitsu Matsui、Shin Takami、Hiromichi Tanaka
DOI:10.1021/jo802615h
日期:2009.3.20
Upon reacting 3,5-O-(di-tert-butyl)silylene-4-thiofuranoid glycal S-oxide (6) with Ac2O/TMSOAc/BF3 center dot OEt2 in CH2Cl2, the additive Pummerer reaction proceeded to furnish the corresponding 1,2-di-O-acetyl-4-thioribofuranose 7. Compound 7 serves as a highly beta-selective glycosyl donor in the Vorbruggen condensation carried out in the presence of TMSOTf. Thus, the 4-thio-beta-D-ribofuranosyl derivatives of uracil, thymine, N-4-acetylcytosine, 6-chloropurine, and 2-amino-6-chloropurine were synthesized. The use of 7 can be extended to the beta-selective synthesis of 4'-thio-C-ribonucleosides.