Chiral 2-C-methylene glycosides and carbohydrate-derived pyrano[2,3-b][1]benzopyrans: synthesis via InCl3 catalyzed stereoselective ferrier rearrangement of 2-C-acetoxymethyl glycal derivatives

TitleChiral 2-C-methylene glycosides and carbohydrate-derived pyrano[2,3-b][1]benzopyrans: synthesis via InCl3 catalyzed stereoselective ferrier rearrangement of 2-C-acetoxymethyl glycal derivatives
Publication TypeJournal Article
Year of Publication2005
AuthorsGhosh, R, Chakraborty, A, Maiti, DK, Puranik, VG
JournalTetrahedron Letters
Volume46
Issue46
Pagination8047-8051
Date PublishedNOV
Type of ArticleArticle
ISSN0040-4039
Keywords2-C-methylene glycoside, InCl3, pyranobenzopyran, Stereoselective
Abstract

2-C-Acetoxymethyl glycal derivatives react with aliphatic alcohols in the presence of InCl3 (30 mol %) to furnish the corresponding 2-C-methylene glycosides in excellent yields and with exclusive alpha-selectivity except for the methyl 2-C-methylene glycosides, which are formed in similar to 2:1 anomeric ratio in favour of the alpha-anomer. The reaction of 2-C-acetoxyglycals with phenols, however, produces the corresponding chiral carbohydrate-derived pyranobenzopyran derivatives via initial Ferrier rearrangement followed by tandem cyclization in excellent yields and moderate to high stereoselectivities in favour of the corresponding 10a-R-pyrano[2,3-b][1]benzopyran derivatives. (c) 2005 Elsevier Ltd. All rights reserved.

DOI10.1016/j.tetlet.2005.09.059
Type of Journal (Indian or Foreign)

Foreign

Impact Factor (IF)

2.347

Divison category: 
Center for Material Characterization (CMC)
Physical and Materials Chemistry