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Ab initio and Density Functional Calculations on the Ring‐Chain Tautomerism of γ‐Oxocarboxylic Acids
Author(s) -
Fabian Walter M. F.,
Bowden Keith
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200101)2001:2<303::aid-ejoc303>3.0.co;2-i
Subject(s) - tautomer , chemistry , ab initio , computational chemistry , conformational isomerism , ring (chemistry) , chain (unit) , ab initio quantum chemistry methods , solvent effects , density functional theory , solvent , stereochemistry , organic chemistry , molecule , quantum mechanics , physics
The results of ab initio (HF, MP2) and density functional (B3LYP) calculations on a series of γ‐oxocarboxylic acids [( Z )‐3‐acetyl or benzoylacrylic and 2‐acetyl or benzoylbenzoic acids] A and their cyclic tautomers B are presented. For the open‐chain tautomers, different rotamers were considered. Bulk solvent effects were considered by using the polarised continuum model (PCM) and were found to be essential for a proper description of the ring‐chain tautomeric equilibrium. Acetyl derivatives generally prefer the cyclic form, whereas for benzoyl derivatives the preference depends on the nature of the link. Introduction of substituents (methyl, phenyl) at C2 and/or C3 for acrylic acid derivatives substantially shifts the equilibrium towards the cyclic form B .