Chemoselective 1-ethylpiperidine hypophosphite (EPHP)-mediated intermolecular radical additions of 1-deoxy-1-halo-1-iodo-alditols to electron-deficient olefins
摘要:
The chernoselective radical reduction of the iodine atom in a series of 1-deoxy-1-halo-1-iodo-alditols with the 1-ethylpiperidine hypophosphite (EPHP)/AIBN system is described. EPHP is also a good chain carrier for the radical addition of gem-dihalocompounds to electron-deficient olefins. Thus, the synthesis of 4-halo-glycooctononitriles and 4-halo-glycoheptononitriles can be achieved by an intermolecular addition of the 1-deoxy-1-halo-alditol-1-yl radical intermediate to acrylonitrile. (c) 2006 Elsevier Ltd. All rights reserved.
Fragmentation of carbohydrate anomeric alkoxy radicals: a new synthesis of chiral 1-halo-1-bromo compounds
作者:Concepción C González、Elisa I León、Concepción Riesco-Fagundo、Ernesto Suárez
DOI:10.1016/s0040-4039(03)01399-6
日期:2003.8
carbohydrates with (diacetoxyiodo)benzene (DIB) in the presence of bromine is a mild procedure for the synthesis of 1-deoxy-1-halo-1-bromo-alditols with one carbon less than the original carbohydrate. The reaction goes through β-fragmentation of the intermediate anomeric alkoxyl radicals. These 1-halo-1-bromo polyhydroxy compounds may be valuable synthetic intermediates in organicsynthesis.