Merging supramolecular catalysis and aminocatalysis: amino-appended β-cyclodextrins (ACDs) as efficient and recyclable supramolecular catalysts for the synthesis of tetraketones
作者:Yufeng Ren、Bo Yang、Xiali Liao
DOI:10.1039/c6ra01002d
日期:——
β-CD were synthesized and employed in the catalytic synthesis of a series of tetraketones as supramolecular catalysts in water for the first time. Yields of 58–97% were obtained with up to 30 examples of substrate. The catalyst could be recycled easily, while a 92% yield and 84% rate of catalyst recovery could be achieved after 8 cycles of catalyst recycling. Moreover, a catalytic mechanism merging
The acridan derivative (1) as a model for NADH reduces alcohols and imines without any external activation by acids whereas similar models such as (2) with equimolar amounts of acetic acid in neutral solvents did not effect any reduction; an analogy with similar reductions by oxidoreductases is demonstrated.
Selective Conversion of Carbon Dioxide to Formaldehyde via a Bis(silyl)acetal: Incorporation of Isotopically Labeled C<sub>1</sub> Moieties Derived from Carbon Dioxide into Organic Molecules
作者:Michael Rauch、Zack Strater、Gerard Parkin
DOI:10.1021/jacs.9b08342
日期:2019.11.6
The conversion of carbon dioxide to formaldehyde is a transformation that is of considerable significance in view of the fact that formaldehyde is a widely used chemical, but this conversion is challenging because CO2 is resistant to chemical transformations. Therefore, we report here that formaldehyde can be readily obtained from CO2 at room temperature via the bis(silyl)acetal, H2C(OSiPh3)2. Specifically
Electrophilic substitution in pyrroles. Part 5. Reaction of dipyrrylmethanes with arenediazonium ions
作者:Anthony R. Butler、Peter T. Shepherd
DOI:10.1039/p29800000113
日期:——
Dipyrrylmethanes react with arenediazonium ions in acidsolution to form azopyrroles and formaldehyde. At low pH cleavage of the methylene bridge is brought about by attack of hydrogen ions, but at higher pH arenediazonium ions assume this role. In the reaction of benzylpyrrole, benzyl alcohol was detected as a product, suggesting formation of a benzyl carbonium ion. The relevance of these studies to the
Functionalisation of saturated hydrocarbons. Part xvii. Reactivity of carbon-carbon double bonds
作者:Derek H.R. Barton、Kyu Wan Lee、Wolf Mehl、Nubar Ozbalik、Li Zhang
DOI:10.1016/s0040-4020(01)90511-3
日期:1990.1
The Gif oxidation systems cleave methylidene olefins into the ketone or aldehyde and formaldehyde. This is considered to be a further manifestation of an Vfe oxenoid species. Similarly, more substituted olefins are oxidized to the corresponding unsaturated ketones or aldehydes. The oxidation of limonene afforded the ketone 24 resulting from methylene cleavage and racemic carvone 25. The latter is considered