BASE CATALYSED REARRANGEMENT OF SOME BROMODEOXYHEPTONOLACTONES

Article abstract of DOI:10.1016/0008-6215(88)84112-0

The behaviour of 7-bromo-2,3,7-trideoxy-D-arabino-heptono-1,4-lactone(1), 7-bromo-2,7-dideoxy- (13), and 7-bromo-3,7-dideoxy-D-gluco-heptono-1,4-lactone (21) towards aqueous base has been studied.With potassium carbonate, each gives a 6,7-epoxide which undergoes subsequent slow hydrolysis.With potassium hydroxide, epoxide migration take place, giving equilibrium mixtures of epoxides which undergo intramolecular substitution by attack of the carboxylate or an alkoxide ion.Thus, 1 is converted into 2,3-dideoxy-L-arabino-heptanoic acid, 13 primarily forms 3,6-anhydro-2-deoxy-L-ido-heptonic acid, and 21 yields 2,5-anhydro-3-deoxy-L-altro-heptonic acid.