ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
On cycloaddition reactions with 3,4-dimethoxyfuranWe describe new cycloadditions of 3,4-dimethoxyfuran (3,4-DF, 1) with various dienophiles. In contrast to furan, the reaction of 3,4-DF with maleic anhydride gives exo- and endo-adducts at approximately the same rate. The thermodynamically more stable product is again the exo-product. Less active dienophiles lead also to mixtures of exo- and endo-adducts, except for citraconic anhydride (methylmaleic anhydride) which forms only the adduct with an endo-methyl group. Dimethylmaleic anhydride could not be reacted with 3,4-DF.All adducts with 3,4-DF contain a hidden 1,2-dicarbonyl group in the form of an endiolether. Its pronounced nucleophilic character allows a series of further additions. Noteworthy are the stereospecific cis-additions of halogens and the preparation of several acetals. Ozonolysis of the enolether in 4 allows the preparation of the hitherto unknown 2r, 3trans, 4trans, 5cis-tetrahydrofuran tetracarboxylic acid and derivatives thereof (5 and 6).
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19790620717
