中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | 3-(2,3,5-tri-O-benzyl-α-D-ribofuranosyl)-1-propene | 93836-22-7 | C29H32O4 | 444.571 |
Addition of a proton to the double bond of 1-C-allyl-O-benzylglycosides gave a 2′-carbonium ion, which in turn reacted intramolecularly, in a regio- and diastereo-selective manner, with the nucleophilic oxygen of the 2-O-benzyl group to form an oxonium intermediate. Subsequent cleavage of the benzyl CO bond led to dioxabicycles in moderate yields. Surprisingly, opposite diastereoselectivities were observed from 1-C-allylglycofuranosides and 1-C-allylglycopyranosides, which produced 2,2′-trans- and 2,2′-cis-dioxabicycles, respectively.Key words: C-glycoside, olefin, cyclization, oxocarbonium, dioxabicycles.