ISSN:
0170-2041
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Cycloaddition with Unsaturated Carbohydrates, III. - The Stereochemistry of the Diels-Alder Reaction with Hex-2-enopyranoside and Hex-2-enopyranosid-4-ulosesThe diene addition to ethyl 4,6-di-O-acetyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranoside (1) formed only the α-D-manno adduct 2. With alkyl 2,3-dideoxy-α(β)-D-glycero-hex-2-enopyranosid-4-uloses 3a and b, the L- and D-erythro adducts 4a, b and 5a, b, respectively, are prepared. They tautomerize to give the D- and L-threo stereoisomers 6a, b, and 7b, respectively. The benzo-[2,3]hexopyranosid-4-uloses were reduced stereoselectively by NaBH4 to hexopyranosides. The structure of methyl 2,3-dideoxy-1′,2′,3′,6′-tetrahydro-4′,5′-dimethyl-β-D-glycero-D-threo-benzo-[2,3]hexopyranosid-4-ulose (6b) was determined by an X-ray analysis.
Notes:
Die Dien-Addition an Ethyl-4,6-di-O-acetyl-2,3-didesoxy-α-D-erythro-hex-2-enopyranosid (1) führt ausschließlich zum α-D-manno-Addukt 2. Mit den Alkyl-2,3-didesoxy-α(β)-D-glycero-hex-2-enopyranosid-4-ulosen 3a und b entstehen je ein L- und D-erythro-Addukt 4a, b bzw. 5a, b. Diese tautomerisieren zu den D- und L-threo-Stereoisomeren 6a, b und 7b. Die Benzo[2,3]hexo-pyranosid-4-ulosen wurden mit NaBH4 stereoselektiv zu Hexopyranosiden reduziert. Die Struktur von Methyl-2,3-didesoxy-1′,2′,3′,6′-tetrahydro-4′,5′-dimethyl-β-D-glycero-D-threo-benzo-[2,3]hexopyranosid-4-ulose (6b) wurde durch Röntgenstrukturanalyse bestimmt.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.198419840903
