Regioselektive Acylierung von 1,4:3,6-Dianhydro-D-glucit
作者:Peter Stoss、Peter Merrath、Günther Schlüter
DOI:10.1055/s-1987-27878
日期:——
Regioselective Acylation of 1,4:3,6-Dianhydro-D-glucitol Acylation of 1,4:3,6-dianhydro-D-glucitol with anhydrides in the presence of heavy metal salts affords 5-endo-acylates with high regioselectivity, without detectable amounts of the isomeric 2-acylates. Acyl group migration occurs with preference for the 2-exo-position, on heating an acylation mixture, which contains varying amounts of 1,4:3,6-dianhydro-D-glucitol, 2- and 5-monoacylate and 2,5-diacylate, in the presence of reesterification catalysts and whilst distilling off the lower boiling 2-acylate.
Selective Esterification of 1,4:3,6-Dianhydro-D-glucitol
作者:Živorad Čeković、Zorana Tokić
DOI:10.1055/s-1989-27332
日期:——
Esterification of 1,4:3,6-dianhydro-D-glucitol (1) with carboxcylic acids in the presence of 4-dimethylaminopyridine and dicyclohexylcar- bodiimide affords 2-exo-acylates 3 with high regioselectivity, in addition to small amounts of the isomeric 5-endo-acylates 4 and 2,5-diacylates 5.