Reactions of Alkyllithium and Grignard Reagents with Benzoquinone:  Evidence for an Electron-Transfer Mechanism

McKinley, Jason D.; Aponick, Aaron; Raber, Jeffrey C.; Fritz, Christine; Montgomery, David J.; Wigal, Carl T.

doi:10.1021/jo970201u

Cited by 34 publications

(22 citation statements)

References 24 publications

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“…This is in line with the common opinion that anomalous behaviour of Grignard reagents can be explained by invoking a single electron transfer (SET) mechanism [ 23 , 24 ]. It has been reported [ 2 ] that the C–Mg bond dissociation energy is well related to the oxidation potential values of different Grignard reagents (the C–Mg dissociation energy of 23 Kcal/mol corresponds an oxidation potential difference of 1.00 Volt [ 2 ]) and the vinyl- and aryl-Grignard reagents possess the strongest among the C–Mg dissociation energies [ 2 ].…”

Section: Resultssupporting

confidence: 89%

Regioselectivity in Reactions between Bis(2-benzothiazolyl)ketone and Vinyl Grignard Reagents: C- versus O-alkylation—Part III

et al. 2018

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Abstract:The reaction between bis(2-benzothiazolyl)ketone and vinyl Grignard reagents bearing different substituents on the vinyl moiety gave the product derived from attack on the carbonylic carbon-and/or oxygen-atom. The regioselectivity of the attack depends on the kind of substituents bound to the vinylic carbon atoms and on their relative position. The reaction between vinylmagnesium bromide and 2-methyl-1-propenylmagnesium bromide was carried out under different experimental conditions and in the presence of radical scavengers. The results indicate a plausible mechanistic pathway involving radical intermediates in the case of O-alkylation, but a polar ones in the case of classic C-alkylation. This agrees with our previous reports indicating a key role played by the delocalization ability of the substituents bound to the carbonyl group in driving the regioselectivity of the vinylmagnesium bromide attack towards O-alkylation. Further support of this was obtained by diffractometric analysis of four distinct bis(heteroaryl)ketones.

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Section: Resultssupporting

confidence: 89%

Regioselectivity in Reactions between Bis(2-benzothiazolyl)ketone and Vinyl Grignard Reagents: C- versus O-alkylation—Part III

et al. 2018

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“…It is well-known that organolithium compounds and Grignard reagents (except MeLi and MeMgBr) do not give good yields of 1,2-addition products with 1,4-quinones, but instead suffer from singleelectron-transfer processes that result in the formation of the reduced quinone. [43] The only example that we have been able to find is by Yoshida and co-workers who found that phenyllithium will add to the quinone 45 to give a mixture of the regioisomers 46 and 47 in a 1:4 ratio (Scheme 8). [44] Indeed, as expected, all attempts to effect the addition of phenyl magnesium bromide, either commercial material or freshly prepared, to 1,4-naphthoquinone 44 failed.…”

Section: The Michael Addition Approach To 3-phenyl-1-naphtholmentioning

confidence: 95%

“…The major anticipated problem with this approach is the 1,2‐addition to the naphthoquinone 44 . It is well‐known that organolithium compounds and Grignard reagents (except MeLi and MeMgBr) do not give good yields of 1,2‐addition products with 1,4‐quinones, but instead suffer from single‐electron‐transfer processes that result in the formation of the reduced quinone 43. The only example that we have been able to find is by Yoshida and co‐workers who found that phenyllithium will add to the quinone 45 to give a mixture of the regioisomers 46 and 47 in a 1:4 ratio (Scheme ) 44.…”

Section: Introductionmentioning

confidence: 99%

A Succinct Synthesis of the Vaulted Biaryl Ligand Vanol via a Dienone–Phenol Rearrangement

Ding

Xue

Wulff

2011

Chemistry An Asian Journal

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Vanol is a member of the vaulted biaryl family of ligands and it has been proven to be very effective in a number of asymmetric catalytic reactions. The previous synthesis of vanol, while effective, is limited by the cost of reagents involved. The present work evaluates three different approaches to the synthesis of 3-phenyl-1-naphthol, a key intermediate in the synthesis of vanol. The first approach has its key step as the Michael addition of a benzyl Grignard to methyl cinnamate. In the second approach the key step is the first step, a Reformatsky reaction of ethyl bromoacetate and deoxybenzoin. The final and most-efficient approach involves a dienone-phenol rearrangement of a 4-aryl-1-tetralenone generated in-situ from the reaction of 4-chloro-1-naphthol with AlCl(3) and benzene, and preliminary results are reported on the extension of this method to substituted vanol derivatives.

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“…Resonances of the quarternary C(11) of 1 at d 185.3 and the four olefinic atoms C(13), C(9), C(12), and C(10) at d 150.9, 148.7, 127.2, and 127.0, respectively, pointed to the presence of a dienone structure [4]. Eight CH 2 signals between d 29.3 and 29.6 revealed the presence of an alkyl chain.…”

mentioning

confidence: 99%

Antiprotozoal Activity and Cytotoxicity of Novel 1,7-Dioxadispiro[5.1.5.2]pentadeca-9,12-dien-11-one Derivatives fromAmomum aculeatum

Heilmann

Mayr

Brun

et al. 2000

HCA

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Cytotoxicity against the KB cancer cell line as a lead bioactivity-guided fractionation of the petroleum ether extract of rhizomes of Amomum aculeatum Roxb. led to the isolation of three novel dioxadispiro[5.1.5.2]-pentadeca-9,12-dien-11-one derivatives. The structures of aculeatin A (1), aculeatin B (2), and aculeatin C (3) were established as rel-(2R,4R,6S)-and rel-(2R,4R,6R)-4-hydroxy-2-tridecyl-1,7-dioxadispiro[5.1.5.2]pentadeca-9,12-dien-11-one (1 and 2, resp.) and rel-(2R,4R,6R)-2-[4-(3-dodecyl-2-heptyl-3-hydroxy-6-oxocylohexa-1,4-dienyl)-2-oxobutyl]-4-hydroxy-1,7-dioxadispiro[5.1.5.2]pentadeca-9,12-dien-11-one (3) by extensive spectroscopic analyses, particularly 13 C-NMR, inverse-gated 13 C, HMQC, HMBC, NOESY, and INADEQUATE NMR experiments as well as mass spectrometry. The aculeatins represent a novel type of natural products. All compounds showed high cytotoxicity against the KB cell line: 1, IC 50 1.7 mm ; 2, IC 50 2.0 mm ; 3, IC 50 1.6 mm. Additional testing against two Plasmodium falciparum strains as well as against trypomastigote forms of Trypanosoma brucei rhodesiense and Trypanosoma cruzi showed strong activities, particularly against P. falciparum strain K1 (1, IC 50 0.18 mm ; 2, IC 50 0.43 mm ; 3, IC 50 0.37 mm).

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Reactions of Alkyllithium and Grignard Reagents with Benzoquinone: Evidence for an Electron-Transfer Mechanism

Cited by 34 publications

References 24 publications

Regioselectivity in Reactions between Bis(2-benzothiazolyl)ketone and Vinyl Grignard Reagents: C- versus O-alkylation—Part III

Regioselectivity in Reactions between Bis(2-benzothiazolyl)ketone and Vinyl Grignard Reagents: C- versus O-alkylation—Part III

A Succinct Synthesis of the Vaulted Biaryl Ligand Vanol via a Dienone–Phenol Rearrangement

Antiprotozoal Activity and Cytotoxicity of Novel 1,7-Dioxadispiro[5.1.5.2]pentadeca-9,12-dien-11-one Derivatives fromAmomum aculeatum

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