Stereoselective cyclopropanation of unsaturated acetals, using carbohydrates with d-gluco, l-rhamno and d-xylo configurations as chiral auxiliaries
作者:José M. Vega-Pérez、Ignacio Periñán、Margarita Vega、Fernando Iglesias-Guerra
DOI:10.1016/j.tetasy.2008.06.018
日期:2008.7
with CH2I2/ZnEt2 took place with different stereoselectivity, depending on the configuration on the acetal carbon, the size of the acetal ring, the sugar configuration, the protecting group of the hydroxyl groups of the sugar and the substitution of the unsaturated system. The stereochemistry of the new stereogenic centres was then determined by acid hydrolysis of the cyclopropane moiety of the chiral
Stereoselective epoxidation of alkenylidene acetals derived from carbohydrates with d-allo, d-altro, d-galacto, d-gluco and d-xylo configurations
作者:José M. Vega-Pérez、Margarita Vega、Eugenia Blanco、Fernando Iglesias-Guerra
DOI:10.1016/j.tetasy.2007.07.015
日期:2007.8
The synthesis of 2,3-epoxypropylidene acetals of sugar derivativesfrom N-acetyl-2-amino-2-deoxy-d-allopyranose, d-altropyranose, d-galactopyranose, N-acetyl-d-glucosamine, d-glucofuranose and d-xylofuranose is described. The epoxidation with m-CPBA of the corresponding alkenylidene derivatives took place with different stereoselectivities depending upon the sugar configuration, the protecting group