posted on 2005-01-19, 00:00authored byYvan 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.