Retention and apparent inversion during azide displacement of α-triflates of 15-lactones

Abstract

Reactions of azide ion with 2-O-trifluoromethanesulphonates of both 34:67-di-O-isopropylidene-D- glycero -D- talo -hepton-0-15-lactone and of 34;67-di-O-isopropylidene-D- glycero -D- galacto -heptono-1-5-lactone give predominantly 2-azido-2-deoxy-3 4:6 7-di-O-isopropylidene-D- glycero -D- galacto 5-lactone initially which then isomerises under the reaction conditions to 2-azido-2-deoxy-34:67-di-O-isopropylidene-D glycerol -D- talo -heptono-1 X-ray crystal structure analyses of 34;67-di-O-isopropylidene-D- glyceroD -1- talo -heptono-1 5-lactone. and 2-azido-2-deoxy-3 4:6 7-di-O-isopropylidene-D- glycero -D- talo -heptono-15-lactone are reported.