ISSN:
0170-2041
Keywords:
Electrochemistry
;
Coumarins, reduction of
;
Enantioselective protonation
;
Alkaloids
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The optical yield in the alkaloid-catalyzed enantioselective electroreduction of 4-methylcoumarin (1a) was increased from 17% to 47.4% by systematic variation of the electrolysis conditions. The results are explained by an induction mechanism in which the adsorbed protonated alkaloid acts as a chiral proton donor towards a prochiral carbanion derived from 1a. The preferred configuration of the product and the results obtained by variation of the alkaloid structure allow us to propose a model of the transition state. Furthermore, 4-phenylcoumarin (1b) and 4-(trifluoromethyl)coumarin (1c) were reduced with 13.2% and 8.4% ee, respectively.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199319930198
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