Anionic zirconaoxiranes as nucleophilic aldehyde equivalents. Application to intermolecular pinacol cross coupling

Askham, Fredric R.; Carroll, Kevin M.

doi:10.1021/jo00078a006

Cited by 46 publications

(12 citation statements)

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“…In the case of divalent metals, coupling of two such fragments can occur intramolecularly in a metal-bridged bis-ketyl diradical species, affording the 1,2-diol chelate I (Figure ). When appropriate transition metals are used in reductive conditions, the metal atom is inserted into the carbonyl π-bond, giving rise to a metallaoxirane II , representing an umpoled carbonyl unit that can thereafter react with a second non-umpoled carbonyl molecule. A related reaction is McMurry coupling in which two carbonyl units undergo reductive dimerization in the presence of TiCl 3 , or TiCl 4 and a reducing metal such as zinc, to give an olefin.…”

Section: Introductionmentioning

confidence: 99%

On the Mechanism of Trimethylphosphine-Mediated Reductive Dimerization of Ketones

Ferao

2018

Inorg. Chem.

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High-level single-reference calculations reveal that trimethylphosphine-mediated reductive dimerization of properly substituted (e.g., CF) ketones proceeds via initial formation of an oxaphosphirane intermediate, with the oxygen atom occupying an equatorial position at phosphorus. In the "oxirane route", this oxaphosphirane intermediate loses a trimethylphosphine oxide unit, thus behaving as a carbene transfer agent toward a second carbonyl molecule and giving rise to a carbonyl ylide that cyclizates to the corresponding oxirane. This in turn transfers the carbene unit to a second phosphine molecule, with loss of acetone, affording a phosphorane. The latter undergoes typical Wittig reaction to the final homocoupling product through the oxaphosphetane intermediate. The alternative direct conversion of oxaphosphirane into phosphorane constitutes the lowest energy path as it skips the highest barrier oxirane → phosphorane conversion. The oxirane route is favored by the use of polar solvents and electron deficient carbonyl components. The lowest barrier most exergonic process from oxaphosphirane is the pericyclic cycloaddition of the acetone C═O bond along the endocyclic P-C bond, furnishing the stable 1,3,2-dioxaphospholane product.

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Section: Introductionmentioning

confidence: 99%

On the Mechanism of Trimethylphosphine-Mediated Reductive Dimerization of Ketones

Ferao

2018

Inorg. Chem.

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“…Subsequently, oxidative aglafolin 3 was successfully prepared from 2 via intramolecular keto-ester reductive coupling. In this process, SmI 2 was proved to be the best reductive coupling system after many trials, despite that the Ti 3+ and Zr 3+ were also used in this reduction reaction [7,8]. Through further optimizing, the solvent and other conditions, four isomers of oxidative aglafolin 3 were completely obtained, that is, 2a converting into 3a and 3b, 2b converting into 3c and 3d.…”

Section: Resultsmentioning

confidence: 99%

Studies on Synthesis and Biological Activity of Oxidative Aglafolin Derivatives

Wang

Xie

et al. 2014

Journal of Heterocyclic Chem

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in Wiley Online Library (wileyonlinelibrary.com).The synthesis of the key intermediate of rocaglamide, oxidative aglafolin, was studied, and its diastereoisomers were obtained. The amination of oxidative aglafolin was also investigated, affording amino derivatives. The preliminary bioassay results indicate that these new aglafolin derivatives showed certain degree of insecticidal and repellent activity against Plutella xylostella and Laphygma exigua.

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“…According to our initial scheme, the compound 3b was prepared from 2b via intramolecular keto-ester reductive coupling (Scheme-I). Reductive coupling of carbonyl compounds by Ti 3+ and Zr 3+ are well known 11,12 . In this reaction the Ti 3+ and Zr 3+ were used as the reductive agent, however no reaction took place by TLC monitoring, only crude materials were recovered.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Key Intermediate of Rocaglamide via SmI2 Catalyzed Intramolecular Reductive Coupling Reaction

Wang¹,

Gong²,

Qin³

2014

Asian J. Chem.

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The compound of methyl 8b-hydroxy-6,8-dimethoxy-3a-(4-methoxyphenyl)-1-oxo-3-phenyl-2,3,3a,8a-tetrahydrocyclopenta[b]benzofuran-2-carboxylate (3b), can be obtained with moderate yields under optimum reaction conditions. During this optimization, intramolecular ketone-ester reductive coupling reactions promoted by SmI2 have been studied. The synthetic procedure was successfully applied to the preparation of the key intermediate of the rocaglamide.

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Anionic zirconaoxiranes as nucleophilic aldehyde equivalents. Application to intermolecular pinacol cross coupling

Cited by 46 publications

References 0 publications

On the Mechanism of Trimethylphosphine-Mediated Reductive Dimerization of Ketones

On the Mechanism of Trimethylphosphine-Mediated Reductive Dimerization of Ketones

Studies on Synthesis and Biological Activity of Oxidative Aglafolin Derivatives

Synthesis of Key Intermediate of Rocaglamide via SmI2 Catalyzed Intramolecular Reductive Coupling Reaction

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