Synthesis of four new diastereoisomers of dl-5-hydroxymethyl-1,2,3,4-cyclohexanetetrol

Abstract

Four new diastereoisomers of the pseudo-sugar dl-5-hydroxymethyl-1,2,3,4-cyclohexanetetrol, having (1,2,3,4/5)- ( 2), (1,5/2,3,4)- ( 3), (1,2,3/4,5)- ( 4), and (1,2,4,5/3)-configurations ( 5), have been synthesised by unambiguous sequences from readily available pseudo-sugars. Acetonation of dl-(1,2,4/3,5)-5-hydroxymethyl-1,2,3,4-cyclohexanetetrol with 2,2-dimethoxypropane in N,N-dimethylformamide in the presence of toluene- p-sulfonic acid gave the 1,2:4,7-di- O-isopropylidene derivative ( 9) in good yield. Oxidation of HO-3 in 9 with ruthenium tetraoxide in chloroform gave the ketone 11, which was catalytically hydrogenated to give the 3-epimer ( 12) of 9. Deprotection of 12 gave the 1,2,3,4/5-isomer 2 in good yield. Likewise, compounds 3 and 4 were synthesised from (1,3,5/2,4)- and (1,2/3,4,5)-5-hydroxymethyl-1,2,3,4-cyclohexanetetrol, respectively. Compound 5 was obtained by catalytic hydrogenation of dl-(1,2,4/3)-5-hydroxymethyl-5-cyclohexene-1,2,3,4-tetrol.