ISSN:
0170-2041
Keywords:
Kolbe electrolysis
;
Radical cyclization
;
Electrochemical dehalogenation
;
Prostaglandins
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The key intermediate of a novel synthesis of prostaglandin precursors, (1′R,4′S,3R/S)-3-(cis-4-acetoxycyclopent-2-enyl oxy)-3-ethoxypropionic acid (3), is prepared by two different synthetic sequences: In a first strategy transacetalization of ethyl 3,3-diethoxypropionate (6) with (1R, 4S)-4-acetoxy-1-hydroxy-2-cyclopentene (7) leads to the formation of the mixed acetal 8. By subsequent hydrolysis and acylation 8 could be converted into acid 3 in six steps in 6% overall yield. However, the generation of acid 3 by bromoalkoxidation of 3-ethoxyacrylates 13d, e and subsequent electrochemical reduction proved to be more efficient. In this reduction it is possible to debrominate the α-bromo esters 14d, e and to remove the 2-haloethyl ester group in one step. Using this reaction sequence, we could synthesize acid 3 in five steps in 38% overall yield.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199419940302
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