American Chemical Society
ja046389y_si_002.cif (36.21 kB)

Synthesis of Postulated Molecular Probes:  Stereoselective Free-Radical-Mediated C-Glycosylation in Tandem with Hydrogen Transfer

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posted on 2005-01-19, 00:00 authored by Yvan Guindon, Mohammed Bencheqroun, Abderrahim Bouzide
Reported herein is a strategy employing an addition reaction in tandem with a hydrogen-transfer reaction for the elaboration of C-glycoside-based sialyl Lewis X (sLeX) analogues. Significant stereocontrol was noted when alkyl radicals were reacted with a series of alkoxytaconates. Transition states were proposed to explain the obtained selectivity. Further reaction between an anomeric-centered fucosyl-derived radical and a galactosylated hydroxytaconate provided easy access to C,O-diglycosides as mimics of sLeX. In this case, two 1,3-distant stereocenters were created with high diastereoselectivity using free radical intermediates in a tandem process.