Synthesis of (−)-Conduritol F, (+)-Conduritol B, Cyclophellitol from l-Quebrachitol

The methyl ether of cyclitols with vicinal hydroxyl group was cleaved chemoselectively in preference to both cis- and trans-cyclohexylidene moieties by AlCl3–n-Bu4NI to afford parent alcohols in good yields. (−)-Conduritol F was prepared from l-quebrachitol, an optically active cyclitol from the serum of rubber trees, in five steps by use of the demethylation reaction. The first chiral synthesis of (+)-conduritol B and the total synthesis of cyclophellitol, a novel β-glucosidase inhibitor, are described.