Reaction of 2-deoxy-6-O-[2,3-dideoxy-4,6-O- isopropylidene-2,3-(N-tosylepimino)-α-D-mannopyranosyl]- 4,5-O-isopropylidene-1,3-di-N-tosylstreptamine with potassium hydrogenfluoride
4'-Deoxy-4'-fluorokanamycins A (17) and B (25) have been prepared through fluorinative ring-opening of the D-galacto-3',4'-oxiranes (8 and 21) derived from kanamycin A and B with potassium hydrogenfluoride in ethane-1,2-diol. The mechanism of preponderant formation of the 4'-deoxy-4'-fluoro-D-gluco (9 and 22) over the 3'-deoxy-3'-fluoro-D-gulo derivatives was discussed. In the synthesis of 25, the