10.1002/ejoc.201700588
The study systematically investigates the aromatic tetradehydro Diels-Alder (Ar-TDDA) reaction, focusing on the factors influencing the distribution of linear and angular naphthalene products. The researchers examined how the structure of the linker and the steric bulk of substituents affect product outcomes. They found that the linker’s structure plays a crucial role in determining whether the reaction yields linear or angular products. Externally activated linkers favor linear naphthalenes, while internally activated ones tend to produce angular naphthalenes. The study also explored steric hindrance effects, revealing that increased steric bulk initially favors angular products but reverses this preference beyond a certain threshold.
10.1016/j.tetlet.2004.09.025
The study presents a novel approach for constructing quaternary centers on cycloalkane rings, which is a significant challenge in synthetic chemistry. The researchers utilized a combination of Birch reduction-allylation and Cope rearrangement on o-anisic acid derivatives to synthesize 2-acyl-3-cyclohexenone derivatives. They successfully generated rearrangement substrates and achieved high yields of 2-cyclohexenone products through thermal equilibration in 1,2-dichlorobenzene. Notably, the Cope rearrangement of a specific substrate resulted in the formation of a new quaternary center with excellent yield, marking the first example of such synthesis on a cycloalkenone ring via Cope rearrangement. This method could serve as a powerful tool for creating substituted 2-cyclohexenones, offering a potentially versatile synthetic intermediate with potential for 1,3-chirality transfer and access to enantiomerically pure products.
10.1021/jo001100q
The research focuses on the synthesis and characterization of a novel dyad molecule based on C60 (buckminsterfullerene) and bis(4′-tert-butylbiphenyl-4-yl)aniline (BBA) donor. The purpose of this study was to investigate the intramolecular charge-transfer interactions between the C60 moiety and the electron donor, BBA, with the aim of contributing to the development of artificial photosynthetic systems. The researchers synthesized the dyad 2 through a 1,3-dipolar addition of diazo compounds to C60 and characterized it using cyclic voltammetry (CV) and UV-vis spectra. The results indicated clear evidence of intramolecular charge-transfer interactions, as shown by a positive shift in the reversible oxidation wave of 2 compared to BBA in CV measurements and a significant hyperchromic effect in the UV-vis spectra. Chemicals used in the process included C60, BBA, tosylhydrazone 1, NaOCH3, and o-dichlorobenzene (ODCB), among others. The conclusions drawn from the study were that the synthesized C60-BBA dyad exhibited obvious evidence of intramolecular charge-transfer interactions in the ground state, which could have implications for the development of novel molecular electronic devices.
10.1246/bcsj.64.3682
The research explores a novel Claisen rearrangement reaction involving 2-phenylsulfinyl-2-propenyl phenyl ethers to produce functionalized phenols and 2-methylbenzofurans. The study aims to develop a new synthetic route for these compounds, which have potential applications in organic synthesis and pharmaceuticals. The key chemicals used include 2-phenylsulfinyl-2-propenyl phenyl ethers (2a-d), which undergo thermal rearrangement to form the corresponding phenols (3a-d). These phenols then participate in Michael reactions with various nucleophiles to produce functionalized phenolic adducts (5a-d). Additionally, O-alkylation of the initial rearrangement products with specific synthons followed by [3,3] sigmatropic rearrangement leads to the formation of 7-substituted 2-methylbenzofurans (8a-b). The research concludes that this new route is efficient and versatile, providing a promising method for synthesizing a wide variety of hetero derivatives with potential physiological properties. The use of 1,2-dichlorobenzene as a solvent significantly improves the yield of the products, and the structures of the compounds are confirmed through NMR and IR spectroscopy.
10.3762/bjoc.6.33
The research presents a novel synthetic approach to C3-carbocyclic spirooxindoles using a thermal tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition reaction. The purpose of this study was to develop a concise and efficient method to synthesize densely functionalized spirooxindoles, which are rare structural motifs with potential applications in pharmaceuticals and natural product synthesis. The reaction involves a thermal [3,3]-sigmatropic rearrangement of propargylic acetates to form allenyl acetates, which then undergo a [2 + 2] cycloaddition with an alkyne to produce the desired spirooxindoles. The study concluded that this tandem reaction is highly selective for the distal double bond of the allene, even with densely functionalized substrates, and provides a rapid increase in molecular complexity. The method is tolerant of various functional groups and can be performed in solvents like 1,2-dichlorobenzene or N-methylpyrrolidinone. The research demonstrates a rare example of a thermal [3,3]-sigmatropic rearrangement of a propargylic acetate, expanding the synthetic utility for accessing complex spirooxindole architectures.
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