The formation of isopropylidene acetals of erythritol and ribitol under conditions of kinetic control

Article abstract of DOI:10.1016/0008-6215(90)80137-R

The isopropylidenation of erythritol, under conditions of kinetic control, employing 2-methoxypropene, yielded the 1,2:3,4- (1, 50percent), the 1,4:2,3- (2, 18percent), and the novel 1,3:2,4-diacetal (3, 5percent).Under similar conditions, ribitol gave the known 1,2:4,5- (4, 36percent) and 1,4:2,3-diacetal (7, 3percent) together with the new 1,3:4,5- (8, 12percent) and 1,3:2,5- diacetal (11, 5percent), a further example of a dioxepane ring. 13C-N.m.r. and 1H-n.m.r. spectroscopy showed that the 1,3-dioxane rings in 3, 8 and 11 adopt chair conformations.In 9, the p-nitrobenzoate of 8, the dioxane chair is flattened.The product composition is compared with that from the equilibrated system.