Some Cyclopentenones and Supposed Cyclopentenones

Yates, Peter; Yoda, Naoya; Brown, William G.; Mann, B. R.

doi:10.1021/ja01534a050

Cited by 32 publications

(5 citation statements)

References 5 publications

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“…A similar situation occurs for c j~l opentanone (IG), which also exhibits a split carbonyl band, ancl for certain A2-cyclopentenones that have been studied by Yates and his collabol-atom (17,18). I n both the latter cases it has been sho\vn that the splitting of the carbony1 band must i~~v o l v e an intramolecular vibrational property of the molecule, since it disappears when certain of the h~.drogen atoms are excliangecl for deuterium.…”

Section: Discussionmentioning

confidence: 73%

The Carbonyl Stretching Bands in the Infrared Spectra of Unsaturated Lactones

Jones¹,

Angell²,

Ito³

et al. 1959

Can. J. Chem.

183

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Certain types of unsaturated lactones exhibit two bands in the region of the spectrum associated with the C=O stretching vibrational mode. This is observed both in the infrared and Raman spectra.The infrared spectra of 23 simple saturated and unsaturated lactotles have been examined in an attempt t o determine the structural features with which this carbonyl band splitting is associated. I t appears to be common to most unsaturated five-and six-membered ring lactones in which the double bond is conjugated with the carbonyl group, though one well-established exception has been observed. The relative intensities of the two bands are extremely sensitive to changes in the polarity of the solvent; they also vary reversibly with temperature but are indepenaent of concentration.The s~l i t t i n a of the C=O stretchina band is attributed to an intramolecular vibrational effect similar 'to that which occurs i' n cyclopentanone and in certain Az-cyclopentenone derivatives. Its possible dependence on Fermi resonance with the overtone of a lower lying fundamental vibration is discussed.Similar effects occur in other types of carbonyl compounds, such as benzoyl chloride and cyclic five-membered ring anhydrides, and care is needed to distinguish carbonyl band splitting of this kind from that associated with equilibria between conformational isomers.

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Section: Discussionmentioning

confidence: 73%

The Carbonyl Stretching Bands in the Infrared Spectra of Unsaturated Lactones

Jones¹,

Angell²,

Ito³

et al. 1959

Can. J. Chem.

183

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“…To start our project and investigate the feasibility of the NC in NaDESs, we chose the symmetric tetra-substituted dienone 1a as a model substrate. 32 Various choline chloride (ChCl)carboxylic acid based NaDESs were tested on the base of their ability to convert 1a into the product cyclopentenone 2a (Table 1). At first, ChCl/L-(+)-lactic acid in 1:2 molar ratio was tested and revealed ineffective in promoting the reaction at room temperature, even after 24 h (Table 1, entry 1).…”

Section: Resultsmentioning

confidence: 99%

Natural deep eutectic solvents as an efficient and reusable active system for the Nazarov cyclization

et al. 2020

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“…In order to evaluate the geometrical and energetic effects of protonation on the electrocyclization, , we first carried out ab initio calculations based on the density functional theory, , and the second-order Møller−Plesset perturbation, using 1,4-pentadien-3-one (divinyl ketone) 7 as a simple model (Chart ). Although the intermediacy of the O -monoprotonated divinyl ketones such as 8 is well-established in the Nazarov-type cyclization, , we assume here a hypothetical O,O -diprotonation of the divinyl ketone (i.e., 9 ) in order to consider the effect of O,O -diprotonation on geometry and energy. Previous studies showed that several stationary structures of neutral 1,4-pentadien-3-one (divinyl ketone) 7 and O -protonated 1,4-pentadien-3-one 8 are possible.…”

Section: Resultsmentioning

confidence: 99%

“…It is well known that cyclization reactions of divinyl ketones (1,4-pentadien-3-ones) to 2-cyclopentenones, i.e., Nazarov and related reactions, are catalyzed by acids. , These reactions are relevant to the prototype electrocyclization of the pentadienyl cation to the cyclopentyl cation , However, the analogous cyclization reaction of benzophenone did not proceed even on heating in a strong acid such as trifluoromethanesulfonic acid (TFSA). As judged from the basicity of benzophenone, O -protonated benzophenone, which may have a 3-hydroxy-1,4-pentadienium character, should be formed in TFSA.…”

mentioning

confidence: 99%

Superacid-Catalyzed Electrocyclization of 1-Phenyl-2-propen-1-ones to 1-Indanones. Kinetic and Theoretical Studies of Electrocyclization of Oxonium−Carbenium Dications

1997

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Strongly acidic conditions are required to induce the Nazarov-type cyclization of aryl vinyl ketones, although chemical analogy with the Nazarov reaction would superficially imply a straightforward electrocyclization reaction of the O-protonated monocation. In this paper we describe the superacid-catalyzed prototype cyclization of 1-phenyl-2-propen-1-ones. The acidity dependence of these cyclization reactions as revealed by kinetic measurements strongly suggests the involvement of the O,O-diprotonated dication rather than the O-protonated monocation. That is, the cyclization of 1-phenyl-2-propen-1-ones represents an electrocyclization of the oxonium−carbenium dication. We also describe the effect of substituents at the 2-position of 1-phenyl-2-propen-1-ones. Ab initio calculations, based on the density functional theory, support the idea that electrocyclization of the dication is energetically more favarable than that of the monocation.

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Some Cyclopentenones and Supposed Cyclopentenones

Cited by 32 publications

References 5 publications

The Carbonyl Stretching Bands in the Infrared Spectra of Unsaturated Lactones

The Carbonyl Stretching Bands in the Infrared Spectra of Unsaturated Lactones

Natural deep eutectic solvents as an efficient and reusable active system for the Nazarov cyclization

Superacid-Catalyzed Electrocyclization of 1-Phenyl-2-propen-1-ones to 1-Indanones. Kinetic and Theoretical Studies of Electrocyclization of Oxonium−Carbenium Dications

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