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Mechanism of reactions of unsaturated ethers and thioethers IV: Acid catalyzed rearrangement of ethoxyethynyl- and ethylthioethynyl-carbinols

✍ Scribed by G. L. Hekkert; W. Drenth

Publisher
Elsevier Science
Year
2010
Tongue
English
Weight
810 KB
Volume
80
Category
Article
ISSN
0165-0513

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✦ Synopsis

Abstract

The rearrangement of ethoxyethynyl‐carbinols into unsaturated esters was investigated in acidic aqueous solution. The reaction is general acid catalyzed and β‐hydroxy esters are by‐products. There exists a simple relation between the ratio of β‐hydroxy ester to unsaturated ester and the concentration of hydroxyl and acetate ions. The two products are formed in a common rate determining step, which is a proton addition to the β‐carbon atom of the carbinol. It is suggested, that the hydroxyl group participates and that a four‐membered ring intermediate is formed in this slow step: magnified image Ethylthioethynyl‐carbinols behave similary.

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