FLUORINATED CYCLITOLS - AN IMPROVED SYNTHESIS OF 5-DEOXY-5-FLUORO-MYO-INOSITOL, ITS DEUTERIUM LABELING, AND SYNTHESIS OF A 5,5-GEM-DIFLUORO ANALOG

An improved synthesis of 5-deoxy-5-fluoro-myo-inositol is provided via the reaction of diethylaminosulfur trifluoride (DAST) with the versatile intermediate, 1,4,6-tri-O-benzyl-2,3-O-cyclohexylidene-neo-inositol (I), followed by appropriate deprotection reactions. Reaction of DAST with the 5-keto analogue of I gave the gem-difluoro compound, which upon deprotection afforded 5-deoxy-5,5-difluoro-myo-inositol. A 1H-n.m.r. study of the deuteration of 5-deoxy-5-fluoro-myo-inositol with Raney nickel-deuterium oxide revealed that the equatorial H-2 proton was most rapidly exchanged, followed by the sterically identical H-1 and H-3 protons, which exchanged at a significantly slower rate. © 1990.