MODIFIED PREPARATION METHOD OF TRIFLUOROMETHYLATED PROPARGYLIC ALCOHOLS AND ITS APPLICATION TO CHIRAL 2,6-DIDEOXY-6,6,6-TRIFLUOROSUGARS

Convenient generation of 3,3,3-trifluoropropynyl anion was realized from 2-bromo-3,3,3-trifluoropropene, and the anion's reaction with various electrophiles proceeded in excellent isolated yields. One of the pro ducts, 1-(benzyloxy)-6,6,6-trifluoro-4-hexyn-3-ol (4b), was further employed for the diastereoselective construction of 2,6-dideoxy-6,6,6-trifluorosugars after enzymatic optical resolution and osmium dihydroxylation of the corresponding olefins. The strongly electron-withdrawing trifluoromethyl moiety, significantly affecting the nucleophilic nature of neighboring functionalities, allows the ready differentiation of hydroxy groups by routine chemical transformation, which results in the shortening of the reaction sequence.