RESUMO
Regioselective protection of primary hydroxyl group in nucleoside and carbohydrate analogs was accomplished using dimethoxytrityl alcohol (DMTr-OH) or dimethylpixyl alcohol (DMPx-OH) in presence of copper(II)nitrate as a Lewis acid catalyst. Excellent selectivity was observed for the protection of primary hydroxyl group over secondary while glycosidic bond remain unaffected. Utility of this methodology was further exemplified via DMTr- and DMPx-protection of alipahtic acyclic and cyclic diols.
Assuntos
Álcoois/química , Carboidratos/química , Cobre/química , Nitratos/química , Nucleosídeos/química , Xantenos/química , Ácidos Acíclicos/química , Catálise , Estrutura Molecular , Oxirredução , EstereoisomerismoRESUMO
We examined the catalytic enantioselective fluorination of 3-(2-arylacetyl)-2-thiazolidinones 1 with N-fluorobenzenesulfonimide (NFSI) by DBFOX-Ph/metal complexes under a variety of conditions. After optimization of the metal salts, solvents and additives, we found that the fluoro-2-thiazolidinones 2 were obtained in good to high yields with moderate to good enantioselectivities (up to 78% ee) when the reaction was carried out in the presence of DBFOX-Ph (11 mol%), Ni(ClO(4))(2).6H(2)O (10 mol%) and 2,6-lutidine (0 or 1.0 equiv) in CH(2)Cl(2).