J. Gelas, D. Horton
Dec 1, 1978
Citations
0
Influential Citations
58
Citations
Journal
Carbohydrate Research
Abstract
Abstract The major product obtained on acetonation of d -mannose with a 2-molar excess of isopropenyl methyl (or ethyl) ether is 4,6- O -isopropylidene-α- d -mannopyranose ( 3a ), the product of kinetic acetonation: a larger excess of the reagent leads, to the 2,3:4,6-diisopropylidene acetal ( 6 ). The course of the reaction and side-products formed were examined in detail. The 1,2,3-triacetate of 3a was deacetonated to give α- d -mannopyranose 1,2,3-triacetate; similar reactions were performed on the β anomers. The 1-acetate of the diacetal 6 could be selectively deacetonated to give 1- O -acetyl-2,3- O -isopropylidene-α- d -mannopyranose. The reactions provide access to protected derivatives of d -mannose, and partially acylated derivatives, having modes of substitution different from those obtainable by classical acetonation procedures conducted under conditions of thermodynamic control.