Efficient and Stereoselective Syntheses of Isomerically Pure 4-Aminotetrahydro-2H-thiopyran 1-Oxide Derivatives

Efficient and stereoselective syntheses of isomerically pure 4-aminotetrahydro-2H-thiopyran 1-oxide derivatives have successfully been achieved. Isomerically pure (4-nitrophenyl)sulfonyltetrahydro-2H-thiopyran 1-oxides were identified by Xray crystallographic analyses, and isomerically pure sulfoxide derivatives were characterized by H-1 NMR. An oxidation reaction of tert-buty1(4-nitrophenyl)sulfonyl(tetrahydro-2H-thiopyran-4-71)carbamate with Oxone provided steric control, affording its trans sulfoxide with high efficiency and selectivity. From the obtained trans sulfoxide derivatives, cis sulfoxide derivatives were synthesized conveniently by a hydrogen chloride catalyzed isomerization.