1.
Chem Pharm Bull (Tokyo)
; 70(8): 589-593, 2022.
Artículo
en Inglés
| MEDLINE
| ID: mdl-35908925
RESUMEN
Some terpenyl 2,3,4-tri-O-acetyl-α-D-glucuronide methyl esters were facilely synthesized from commercially available methyl 1,2,3,4-tetra-O-acetyl-ß-D-glucuronate and terpenoid alcohols in the presence of bis(trifluoromethanesulfonyl)imide (Tf2NH) in dichloromethane (DCM) in good yields. The predominant α-selectivity at the anomer position is caused via transition state in which the neighboring group participation of the methoxycarbonyl group at C-6 stabilizes the oxonium intermediate by forming 1C4 conformation. The intermediate accelerates the glucuronidation reaction despite the use of the acetyl group, which is not a good activating group in general glycosylation reactions, as the activating group.