Wittig-selectivity in mixed ketones: exploring 1,3-interaction and enolization

Ghosh, Asitanga; Chakraborty, Indrajit; Adarsh, N. N.; Lahiri, S. K.

doi:10.1016/j.tet.2009.11.006

Cited by 12 publications

(4 citation statements)

References 27 publications

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“…36 -M echanistic studies on reactions of ketones. 37 -Demonstration by us of a unified mechanism for the Li saltfree Wittig reaction of all phosphonium ylide ty pes from reactions of -heteroatom-substituted aldehydes. 38,39 25 -A study of the decomposition of the OPA intermediate (see later), which indicates that its decomposition may occur by a single step.…”

Section: Ementioning

confidence: 99%

The modern interpretation of the Wittig reaction mechanism

2013

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Section: Ementioning

confidence: 99%

The modern interpretation of the Wittig reaction mechanism

2013

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“…5,6-Dibenzoyl-4-phenylbicyclo[2.2.2]oct-5-en-2-one ( 7a ) and 5,6-dibenzoyl-4-isopropenylbicyclo[2.2.2]oct-5-en-2-one ( 7b ) have been prepared through Diels–Alder reaction between substituted silyloxycyclohexa-1,3-dienes 8a and 8b [ 17 – 18 ] and dibenzoyl acetylene ( 9 ) followed by hydrolysis of the silyloxy adduct ( Scheme 4 ).…”

Section: Resultsmentioning

confidence: 99%

“…Both of the molecules contain electron-acceptor groups like phenyl and isopropenyl at its bridgehead position (C-4) and these groups were bulkier than the earlier reported one. [17,18] and dibenzoyl acetylene (9) followed by hydrolysis of the silyloxy adduct (Scheme 4). Both 7a and 7b showed an enhanced (n,π*) absorption band near 300 nm (log ε ≈ 3.5) along with an additional weak band near 343 nm (log ε ≈ 2.5) in their UV spectra as expected for δ-keto-α,β-enone [7].…”

Section: Formation Of An Exceptionally Stable Ketene During Phototranmentioning

confidence: 99%

Formation of an exceptionally stable ketene during phototransformations of bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

Ghosh¹

2020

Beilstein J. Org. Chem.

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Photochemical reactions of bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores like a 5,6 dibenzoyl moiety and bulky electron-deficient substituents like phenyl or isopropenyl at the bridgehead position were analyzed for the first time in different solvents and upon irradiation with different wavelengths. In all cases, a regioselective photoinduced 1,5-phenyl migration leading to vinyl ketenes from the more congested site of the molecule to the less congested one has been observed. The ketenes were exceptionally stable both in air and solution. Its stability studies in acetonitrile through time-dependent UV absorption spectra revealed that it remained almost unchanged at least for a couple of weeks.

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“…Both of the molecules at its bridgehead position (C-4) contain electron acceptor groups like phenyl & vinyl and these groups were bulkier than the earlier reported one. oct-5-en-2-one (7) have been prepared through [4+2] DielsAlder cycloaddition reaction between substituted silyoxy cyclohexa-1,3-dienes (8a-b)[12,13] and dibenzoyl acetylene (9) followed by hydrolysis of the silyoxy adduct(Scheme 3). Reagent and condition: a) dry benzene, overnight stirring under argon, b) 5% methanolic-HCl (5 mL), 20 min…”

mentioning

confidence: 99%

Formation of exceptionally stable ketene during photo transformations of Bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

Ghosh¹

2019

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Photoreaction of Bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores like 5,6 dibenzoyl moiety and phenyl or isopropenyl like electron withdrawing groups at the bridgehead position have been checked in different solvent and different wavelength. In all cases regioselective 1,5-photophenyl migration leading to vinyl ketenes from more congested site of the molecule to the less one have been observed. The ketenes were exceptionally stable both in air and in solution. Its stability studies in acetonitrile through time dependent UV absorbance spectra revealed that it remained almost unchanged at least for couple of weeks.

show abstract

Wittig-selectivity in mixed ketones: exploring 1,3-interaction and enolization

Cited by 12 publications

References 27 publications

The modern interpretation of the Wittig reaction mechanism

The modern interpretation of the Wittig reaction mechanism

Formation of an exceptionally stable ketene during phototransformations of bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

Formation of exceptionally stable ketene during photo transformations of Bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

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