Premium
THE ENOL OF ACETOACETIC ACID: A COMPUTATIONAL STUDY OF THE RELATIVE STABILITIES OF THE KETONE AND CARBOXYLIC ACID ISOMERS
Author(s) -
Hoz S.,
Kresge A. J.
Publication year - 1997
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199703)10:3<182::aid-poc873>3.0.co;2-n
Subject(s) - chemistry , tautomer , ketone , enol , ab initio , keto–enol tautomerism , carboxylic acid , medicinal chemistry , acetoacetic ester synthesis , conjugated system , computational chemistry , stereochemistry , organic chemistry , catalysis , polymer
Ab initio molecular orbital calculations at the MP2/6–311+G**//MP2/6–311+G** level show that the enol tautomer of acetoacetic acid in which the ketone group is enolized, 2 , is more stable than its isomer in which the carboxylic acid group is enolized, 3 , by 11·3 kcal mol −1 . This difference may be attributed to a difference in the strength of resonance interactions between the carbonyl and hydroxyl groups of the enols: the carbonyl group in both isomers is conjugated with two hydroxyl groups, but in the acid enol, 3 , both interactions are vinylogous, whereas in the ketone enol, 2 , one of the vinylogous effects is replaced by a stronger direct interaction. © 1997 by John Wiley & Sons, Ltd.