Reactions of Peracids. V.<sup>1</sup> The Reaction of Substituted Acetophenones with Perbenzoic Acid<sup>2</sup>

Friess, S.L.; Soloway, Albert H.

doi:10.1021/ja01152a122

Cited by 41 publications

(15 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2). A similar trend is also observed in the analogous organic BV reaction 27 and in a recent computational study of BV insertion within Pt(II)-aryl complexes. 28 An examination of the coordination energy shows that a more electron-donating X impedes the coordination of HOO − to Re.…”

Section: Resultssupporting

confidence: 84%

The para-substituent effect and pH-dependence of the organometallic Baeyer–Villiger oxidation of rhenium–carbon bonds

et al. 2012

View full text Add to dashboard Cite

We studied the Baeyer-Villiger (BV) type oxidation of phenylrhenium trioxide (PTO) by H 2 O 2 in the aqueous phase using Quantum Mechanics (density functional theory with the M06 functional) focusing on how the solution pH and the para-substituent affect the Gibbs free energy surfaces. For both PTO and MTO (methylrhenium trioxide) cases, we find that for pH > 1 the BV pathway having OH − as the leaving group is lower in energy than the one involving simultaneous protonation of hydroxide. We also find that during this organometallic BV oxidation, the migrating phenyl is a nucleophile so that substituting functional groups in the para-position of phenyl with increased electron-donating character lowers the migration barrier, just as in organic BV reactions. However, this substituent effect also pushes electron density to Re, impeding HOO − coordination and slowing down the reaction. This is in direct contrast to the organic analog, in which para-substitution has an insignificant influence on 1,2-addition of peracids. Due to the competition of the two opposing effects and the dependence of the resting state on pH and concentration, the reaction rate of the organometallic BV oxidation is surprisingly unaffected by parasubstitution.

show abstract

Section: Resultssupporting

confidence: 84%

The para-substituent effect and pH-dependence of the organometallic Baeyer–Villiger oxidation of rhenium–carbon bonds

et al. 2012

View full text Add to dashboard Cite

show abstract

“…[6] Although the migration is accepted to be the rate-determining step (RDS), some kinetic results for the reaction have been controversial regarding this issue. [3,[7][8][9][10] It has been noted that when the ketone is unsymmetrical, groups with better capacity to stabilize the incipient positive charge will migrate more readily, though other factors may also be involved. [3,11,12] Despite extensive studies of the effects of substituents on the rates of the BV rearrangement, not much detailed information is known regarding the correlation between the substitution pattern of the ketone and its reactivity.…”

Section: Introductionmentioning

confidence: 99%

Substituent effects in the Baeyer–Villiger reaction of acetophenones: a theoretical study

Reyes

Álvarez-Idaboy

Mora‐Diez

2008

J of Physical Organic Chem

View full text Add to dashboard Cite

This paper reports the first complete theoretical study of substituent effects on the mechanism of the Baeyer-Villiger (BV) reaction in non-polar solvents taking into account the lowest-energy mechanism that has been proposed for this rearrangement which is non-ionic and fully concerted. The BV reaction of p-substituted acetophenones, p-XC 6 H 4 COCH 3 (X ¼ NO 2 , CN, H, CH 3 , OCH 3 ), with performic (PFA) and trifluoroperacetic (TFPAA) acids, catalyzed by formic (FA) and trifluoroacetic (TFAA) acids, respectively, using the MPWB1K functional and the 6-311G(d,p) and 6-311RRG(d,p) basis sets, are studied. Solvent effects are taken into account by means of the PCM continuum model using dichloromethane as solvent. Electron-donating substituents on the aryl group have a relatively small activation effect on the first step, but a pronounced activation effect on the second to the point of being able to change the rate-determining step (RDS) of the reaction, as observed in the case of p-methoxyacetophenone with TFPAA acids. After analyzing the changes in Gibbs free energy of activation, geometrical parameters, and charge distributions of the transition states (TSs), explanations are provided for the two distinct effects that substituents on the ketone have on the kinetics of the addition and migration steps of the BV oxidation. The effect of the acid/peracid pair used is also discussed.

show abstract

“…[8,10,11,13 -16] Since all groups attached to the carbonyl carbon of acetophenones migrate in preference to the methyl group, substituted acetophenones show a strong preference for ester formation. [17,18] For other aromatic alkyl ketones, migration of the alkyl group depends on its structure, while the migration of the aryl group depends on the electron-donating or electron-withdrawing properties of the substituents. [8,13] For benzophenones it was established that the product selectivity is strongly dependent on the type and position of the substituents in the phenyl rings.…”

Section: Introductionmentioning

confidence: 99%

Enzymatic Baeyer–Villiger Oxidation of Benzaldehydes

Moonen¹,

Westphal²,

Rietjens

et al. 2005

Adv Synth Catal

View full text Add to dashboard Cite

The selectivity of the chemical Baeyer-Villiger oxidation of benzaldehydes depends on steric and electronic factors, the type of oxidizing agent and the reaction conditions. Here we report on the enzymatic Baeyer-Villiger oxidation of fluorobenzaldehydes as catalyzed by the flavoprotein 4-hydroxyacetophenone monooxygenase (HAPMO). HAPMO was most active with 4-amino-and 4-hydroxybenzaldehydes. With these compounds significant substrate inhibition occurred. Monofluoro-and difluorobenzaldehydes were readily oxidized by HAPMO without substrate inhibition. 19F NMR analysis revealed that 4-fluoro-, 2,6-difluoro-, 3,4-difluoro-, 2-fluoro-4-hydroxy-and 3-fluoro-4-hydroxybenzaldehyde were quantitatively converted by HAPMO to the corresponding fluorophenyl formates. These products spontaneously hydrolyzed to fluorophenols. The HAPMO-mediated conversion of 2-fluoro-, 3-fluoro-, 2,3-difluoro-and 2,4-difluorobenzaldehyde yielded, besides fluorophenols, also minor amounts of fluorobenzoic acids. The high preference of HAPMO for the production of fluorophenols is in disagreement with the rule derived from chemical studies that electron-poor benzaldehydes form mainly benzoic acids. This suggests that interactions of the benzaldehyde substrates with amino acids and/or the flavin cofactor in the enzyme active site influence the selection of the migratory group in favor of the phenyl ring.

show abstract

Reactions of Peracids. V.¹ The Reaction of Substituted Acetophenones with Perbenzoic Acid²

Cited by 41 publications

References 0 publications

The para-substituent effect and pH-dependence of the organometallic Baeyer–Villiger oxidation of rhenium–carbon bonds

The para-substituent effect and pH-dependence of the organometallic Baeyer–Villiger oxidation of rhenium–carbon bonds

Substituent effects in the Baeyer–Villiger reaction of acetophenones: a theoretical study

Enzymatic Baeyer–Villiger Oxidation of Benzaldehydes

Contact Info

Product

Resources

About

Reactions of Peracids. V.1 The Reaction of Substituted Acetophenones with Perbenzoic Acid2

Cited by 41 publications

References 0 publications

The para-substituent effect and pH-dependence of the organometallic Baeyer–Villiger oxidation of rhenium–carbon bonds

The para-substituent effect and pH-dependence of the organometallic Baeyer–Villiger oxidation of rhenium–carbon bonds

Substituent effects in the Baeyer–Villiger reaction of acetophenones: a theoretical study

Enzymatic Baeyer–Villiger Oxidation of Benzaldehydes

Contact Info

Product

Resources

About

Reactions of Peracids. V.¹ The Reaction of Substituted Acetophenones with Perbenzoic Acid²