Efficient syntheses of 1-S-alkyl-1-thio-L-ribitols, D-lyxitols and L-xylitols from D-pentono-1,4-lactones.

The thioalkylation of unprotected 5-bromo-5-deoxy-D-ribono, D-arabinono, and D-xylono-1,4-lactone was performed with the alkylthiol-sodium hydride reagent. The corresponding 5-S-alkyl-5-thio-D-pentono-1,4-lactones were isolated in good yields (82-95%). Reduction with NaBH(4) of these derivatives gave the 1-S-alkyl-1-thio-L-ribitols, D-lyxitols and L-xylitols in 85-96% yields.

Three step synthesis of aminocyclohexitols from unprotected aldoses.

We report an efficient three step synthesis of aminocyclohexitols from aldohexoses without the use of protecting groups. Unprotected aldohexoses are selectively halogenated at the primary carbon, the aldehyde function is then transformed into an oxime ether and finally free radical cyclization of these precursors gives aminocyclohexitols.