Preparation of the C1∼C10 fragment of carbonolide B. A relay approach to carbomycin B
摘要:
Reaction of methyl 2,3-anhydro-5,6-O-cyclohexylidene-beta-D-allofuranoside with 2-methyl-2-propenylmagnesium chloride selectively gave methyl 5,6-O-cyclohexylidene-3-deoxy-3-C-(2-methyl- 2-propenyl)-beta-D-glucofuranoside, which was convened into the C1 similar to C10 fragment of carbonolide B by a sequence of reactions involving hydroboration of the prochiral double bond, oxidative cleavage between C5-C6, and subsequent stereoselective three-carbon elongation at the C5 position. (C) 1997 Elsevier Science Ltd.
Regioselective Introduction of 2-Propynyl Groups into the C-2 or C-3 Position of Furanoside Ring
作者:Dai Kubota、Oyo Mitsunobu
DOI:10.1246/cl.1997.517
日期:1997.6
The reaction of methyl 2,3-anhydro-α-D-ribofuranoside or methyl 2,3-anhydro-5,6-O-cyclohexylidene-α-D-allofuranoside with 2-propynyl metallic reagents exclusively gave the corresponding 2-C-(2-propynyl)-arabino-pentofuranosides and 2-C-(2-propynyl)-altro-hexofuranosides, respectively. In contrast, the β-anomers were selectively attacked at the position 3 to afford the corresponding 3-C-(2-propynyl)furanosides
Reaction of methyl 2,3-anhydro-5,6-O-cyclohexylidene-beta-D-allofuranoside with 2-methyl-2-propenylmagnesium chloride selectively gave methyl 5,6-O-cyclohexylidene-3-deoxy-3-C-(2-methyl- 2-propenyl)-beta-D-glucofuranoside, which was convened into the C1 similar to C10 fragment of carbonolide B by a sequence of reactions involving hydroboration of the prochiral double bond, oxidative cleavage between C5-C6, and subsequent stereoselective three-carbon elongation at the C5 position. (C) 1997 Elsevier Science Ltd.