Bronsted acids of anionic chiral Co(III) complexes were found to act as efficient phase-transfer catalysts for the diastereoselective iodoglycosylation or iodocarboxylation of glycals with a variety of alcohols or carboxylic acids, respectively, with N-iodosuccinimide as the iodo cation source. The corresponding 2-deoxy-2-iodoglycosides, including monosaccharides and disaccharides, and 2-deoxy-2-iodoglycosyl
HIGHLY STEREOSELECTIVE SYNTHESIS OF α-D-GLUCOPYRANOSIDES BY THE<i>N</i>-IODOSUCCINIMIDE-PROMOTED INTERNAL CYCLIZATION
作者:Keisuke Suzuki、Teruaki Mukaiyama
DOI:10.1246/cl.1982.1525
日期:1982.10.5
Highly stereoselective cyclizations of hydroxy enol ethers are effected by N-iodosuccinimide to result in the exclusive formation of 2′-deoxy-2′-iodo-α-d-glucopyranosides. An analog of glycolipid is also successfully synthesized according to the present method.
The glycosylations of glycals and alcohols using N-iodosuccinimide (NIS) and a catalytic amount of PPh3 effectively proceeded under mild conditions to provide the corresponding 2-deoxy-2-iodoglycosides in high yields. The reactivity of the iodoglycosylations with PPh3 significantly increased in comparison to that using NIS alone as an activator. In addition, the glycosylations of glycals and alcohols using catalytic amounts of NIS and P(OPh)(3) were effectively realized to give the corresponding 2-deoxyglycosides in high yields.