Kamlesh Sharma* Pages 872 - 876 ( 5 )
Glycosyl donors have been experimentally shown to have a high tendency for acyl transfer to the alcohol nucleophile as a major side product during glycosylation reactions. Therefore, a neighbouring group participatory mechanism of glycosylation is explored using D-galactopyranose based donor having 2-O-acyl functionality by employing density functional theory. The reaction proceeds via galactopyranosyl dioxolenium ion as a stable intermediate, which leads to the formation of α-glycoside 4, orthoester (5 or 6) and acyl transfer 7 as side products. The mechanism of the stereoselective formation of β-glycoside is investigated. Moreover, all the possible intermediates and transition states have been explored.
Selective glycosylation, Density functional theory, Glycosyl donor, Dioxolenium ion, Glycoside.
Department of Chemistry, Faculty of Science, Shree Guru Gobind Singh Tricentenary University, Gurugram 122505, Haryana