Hydration and Hydrolysis of α-Oxo Carboxylic Acid Derivatives and Conjugate Addition to α,β-Unsaturated Carbonyl Compounds:  A Density Functional Study

Janoschek, Rudolf; Fabian, Walter M. F.

doi:10.1021/jo990105o

Cited by 15 publications

(7 citation statements)

References 56 publications

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“…Cyclic transition-state structures are frequently postulated in the literature, [4][5][6]9,10 including for proton transfer in water 12,28 and acid-12 and base-catalyzed [10][11][12] hydrolysis of esters. In pure water or in water-rich solvent mixtures, water-to-water hydrogen bonds predominate and a multiple number of protons participate in the transition state for the hydrolysis of p-methylphenyl trichloroacetate.…”

Section: Resultsmentioning

confidence: 99%

“…For example, reaction of p-nitrophenyl trifluoroacetate is thought to proceed with three protons undergoing bonding changes in an eight-membered transition state (1). 4 A great number of both experimental [4][5][6][7][8] and theoretical [8][9][10][11][12] studies have been devoted to the hydrolysis reactions of aldehydes, ketones, esters and amides. [13][14][15][16][17] It has been observed that the nucleophile attack on a carbonyl group is mediated by water molecules that previously hydrated the carbonyl group.…”

Section: Introductionmentioning

confidence: 99%

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Solvent effect and proton inventory in the hydrolysis of p‐methylphenyl trichloroacetate

Frasson

Brandão

Zucco

et al. 2006

J of Physical Organic Chem

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Hydrolysis of p-methylphenyl trichloroacetate in water-acetonitrile mixtures was studied as a function of water concentration in the range 5.5-55.5 M. The proton inventory technique, in H 2 O-D 2 O mixtures, shows, for a value of D atom fraction in the solvent n ¼ 0.5, deviations from the expected value (for a reaction with one proton being transferred) of 7.5 and 12.3%, for experiments in the presence of 16.6 and 33.3 M L 2 O (L ¼ H or D), respectively. Theoretical treatment of the data obtained at [L 2 O] ¼ 16.6 M using the Gross-Butler equation are consistent with a cyclic transition-state structure with three protons involved. Conversely, similar experiments in the presence of [L 2 O] ¼ 33.3 M show that multiple water molecules are involved in the transition state of the reaction.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Solvent effect and proton inventory in the hydrolysis of p‐methylphenyl trichloroacetate

Frasson

Brandão

Zucco

et al. 2006

J of Physical Organic Chem

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“…Nevertheless, in comparison with the wide availability of empirical works, relatively few computational approaches have addressed the hydrolysis of esters. − In the case of lactone hydrolysis, the disproportion is even larger, computational works being especially scarce.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Lactone Hydrolysis in Neutral and Alkaline Conditions

2013

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The neutral and base-catalyzed hydrolysis of nine carboxylic acid esters was studied using a hybrid supermolecule-PCM approach including six explicit water molecules. The molecules studied included two linear esters, four β-lactones, two γ-lactones, and one δ-lactone: ethyl acetate and methyl formate, β-propiolactone, β-butyrolactone, β-isovalerolactone, diketene (4-methyleneoxetan-2-one), γ-butyrolactone, 2(5H)-furanone, and δ-valerolactone. DFT and ab initio methods were used to analyze the features of the various possible hydrolysis mechanisms. For all compounds, reasonable to very good qualitative and quantitative agreement with experimental work was found, and evidence is provided to support long-standing hypotheses regarding the role of solvent molecule as a base catalyst. In addition, novel evidence is presented for the existence of an elimination-addition mechanism in the basic hydrolysis of diketene. A parallel work addresses the acid-catalyzed hydrolysis of lactones.

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“…[13,14] This process can be understood as a competition between EWGs on either side of the activated double bond. For example, reactions of dimethylamine or methanol with methyl 3,3-bis(trifluoromethyl)propenoate (8) give the corresponding α-adducts, [13] as do additions of thiols to 2,4-dinitro-(e.g., 24) and 2,4,6-trinitrocinnamates. [14] Phosphane-catalyzed reaction of nitrogen nucleophiles with 2-alkynoates redirects the regioselectivity of ad-respect to properties of the substituents.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Study of the Regioselectivity of Michael Additions

Chatfield¹,

Augsten²,

D’Cunha³

et al. 2004

Eur J Org Chem

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Nucleophilic attack at an α,β‐unsaturated carbonyl moiety usually results in conjugate addition at the β‐carbon atom (1,4 or Michael addition) or, occasionally, in addition at the carbonyl carbon atom (1,2 addition). Recently, however, addition at the α‐carbon atom has been observed when strongly electron‐withdrawing groups are positioned at the carbon atom β relative to the carbonyl group [e.g., methyl 3,3‐bis(trifluoromethyl)propenoate (8) and ethyl 3‐(2,4‐dinitrophenyl)propenoate (24)]. We have performed theoretical calculations [HF/6−31+G(d) and B3LYP//HF/6−31+G(d)] for the addition of cyanide anion to model α,β‐unsaturated carbonyl compounds to determine trends in the regioselectivity with respect to properties of the substituents. The difference between the reaction barriers for α‐ vs. β‐addition decreases as the strength of electron‐withdrawing groups increases until, for sufficiently strong electron‐withdrawing groups, α‐addition becomes favored. The calculations are in agreement with the experimental results. We show that the regioselectivity can be predicted from partial atomic charges and properties of the frontier orbitals of the reactants. We also report new experimental evidence of α‐addition to polysubstituted cinnamates and cinnamaldehydes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Hydration and Hydrolysis of α-Oxo Carboxylic Acid Derivatives and Conjugate Addition to α,β-Unsaturated Carbonyl Compounds: A Density Functional Study

Cited by 15 publications

References 56 publications

Solvent effect and proton inventory in the hydrolysis of p‐methylphenyl trichloroacetate

Solvent effect and proton inventory in the hydrolysis of p‐methylphenyl trichloroacetate

Mechanisms of Lactone Hydrolysis in Neutral and Alkaline Conditions

Theoretical and Experimental Study of the Regioselectivity of Michael Additions

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