Alkoxide‐Accelerated [1,3] Sigmatropic Shift of Bicyclo[3.2.1]oct‐6‐en‐2‐ols to 8‐<i>endo</i>‐Hydroxybicyclo[3.3.0]oct‐2‐en‐4‐ones

Chen, Yeh‐Long; Chang, C.P.; Chang, Nein-Chen

doi:10.1002/jccs.199800098

Cited by 3 publications

(1 citation statement)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides thioethers, a practical alternative approach utilizing sulfoxides as the starting materials for the generation of stable ylides was chosen (Scheme , method B) . However, the direct alkylation of sulfoxides to generate the sulfoxonium salts is essentially limited to the reaction of methyl halide with dimethyl sulfoxide (DMSO), and the subsequent deprotonation requires the use of strong bases such as sodium hydride, ,,− sodium methylsulfinylmethylide, − and n -butyllithium . In addition, the ylide generated from DMSO transfers only the methylene group to the electrophiles.…”

Section: Introductionmentioning

confidence: 99%

The Epoxidation of Carbonyl Compounds with a Benzyne-Triggered Sulfur Ylide

et al. 2016

View full text Add to dashboard Cite

An efficient method for the synthesis of epoxides from carbonyl compounds, sulfoxides, and benzyne is presented. The strategy involved an epoxidation by a sulfur ylide which is formed in situ from sulfoxide and benzyne through the S-O bond insertion and deprotonation. This one-pot reaction proceeds under mild and base-free conditions, providing a convenient way to introduce the substituted methylene groups onto the carbonyl carbon.

show abstract

Section: Introductionmentioning

confidence: 99%

The Epoxidation of Carbonyl Compounds with a Benzyne-Triggered Sulfur Ylide

et al. 2016

View full text Add to dashboard Cite

show abstract

Mechanistic Insight into the Formal [1,3]-Migration in the Thermal Claisen Rearrangement

Hou

2012

J. Org. Chem.

View full text Add to dashboard Cite

The thermal formal [1,3]-sigmatropic shift of allyl aryl ethers has been studied in depth experimentally with the aid of the density functional theory (DFT) calculations of the B3LYP function. Three mechanistic possibilities, referred to as the radical, ionic, and concerted mechanisms, have previously been put forth to explain the thermal [1,3]-rearrangement process. However, the intercrossing and radical trapping experiments indicate the rearrangement is an intramolecular process. The computational studies reveal that the concerted C[1,3]-sigmatropic shift suffered from a higher energetic barrier to allow the rearrangement to proceed under the conditions used. However, a tandem O[1,3]-sigmatropic shift with a configuration inversion of the oxygen atom and [3,3]-sigmatropic shift (the Claisen rearrangement) is the most likely pathway for the formal [1,3] rearrangement. Furthermore, the rearrangement experiments with a designed optically active substrate and O[1,3]-sigmatropic shift examples verify the new cascade rearrangement. In addition, computational and experimental studies indicate that water molecule assists the proton shift during the isomerization. The combined methods provide the new insight into the mechanism of the thermal formal [1,3]-migration in the Claisen rearrangement and the novel O[1,3]-sigmatropic shift as well.

show abstract

N[1,3]-sigmatropic shift in the benzidine rearrangement: experimental and theoretical investigation

Hou

2014

Org. Biomol. Chem.

View full text Add to dashboard Cite

The N[1,3]-sigmatropic shift in the benzidine rearrangement has been studied in depth experimentally with the aid of density functional theory (DFT) calculations. The designed substituted N,N'-diaryl hydrazines rearrange exclusively to the expected o/p-semidines and diphenylines. Intercrossing experiments support the intramolecular rearrangement process. Radical trapping experiments exclude the intermediacy of biradicals in the rearrangements. Computational results demonstrate that the o-semidine rearrangement involves a novel N[1,3]-sigmatropic shift and the p-semidine rearrangement proceeds via tandem N[1,3]/N[1,3]-sigmatropic shifts, while the diphenyline rearrangement occurs through cascade N[1,3]/[3,3]-sigmatropic shifts. The proposed mechanism involving the key N[1,3]-sigmatropic shift as the rate-limiting step is in good agreement with reported kinetic isotope measurements. The combined methods provide new insight into the formation mechanism of o/p-semidines and diphenylines in the benzidine rearrangement and support the unprecedented suprafacial symmetry allowed N[1,3]-sigmatropic shift with an inversion of the configuration in the migrating nitrogen atom.

show abstract

Alkoxide‐Accelerated [1,3] Sigmatropic Shift of Bicyclo[3.2.1]oct‐6‐en‐2‐ols to 8‐endo‐Hydroxybicyclo[3.3.0]oct‐2‐en‐4‐ones

Abstract: Bicyclo[3.2.1]oct‐6‐en‐2‐ols 6 are shown to undergo [1,3] sigmatropic shift to afford 8‐endo‐hydroxy‐bicyclo[3.3.0]oct‐2‐en‐4‐ones 8 under the influence of potassium hydride.

Cited by 3 publications

References 17 publications

The Epoxidation of Carbonyl Compounds with a Benzyne-Triggered Sulfur Ylide

The Epoxidation of Carbonyl Compounds with a Benzyne-Triggered Sulfur Ylide

Mechanistic Insight into the Formal [1,3]-Migration in the Thermal Claisen Rearrangement

N[1,3]-sigmatropic shift in the benzidine rearrangement: experimental and theoretical investigation

Contact Info

Product

Resources

About