Preparation and Reactions of 2-Oxa-6-thiabicyclo[3.2.0]-heptanes and 2-Oxa-5-thiabicyclo[2.2.1]heptanes from Pentoses

Abstract:

The preparation of the two diastereoisomeric 3-methoxy-2-oxa-6-thiabicyclo-[3.2.0]heptan-4-ols 4 and 5 from D-xylose 1 via methyl 2,3-anhydro-α-D-ribofuranoside and the corresponding β-anomer is described. Oxidation of 4 and 5 yields the sulfoxides 6 and 7 and the sulfones 8. – On the other hand, the two diastereoisomeric 3-methoxybicyclo[2.2.1]heptan-7-ols 11 and 12 are obtained from methyl 5-acetylthio-5-deoxy-2-O-mesyl-D-xylofuranosides 9 and 10 via Mitsunobu reaction and intramolecular cyclization. – The stereoisomeric counterparts of 4 and 5, 13 and 14, are obtained in only four steps from L-arabinose.