Counterion effects in iminium-activated electrophilic aromatic substitutions of pyrroles.

Electrophilic substitution of pyrroles by a,b-unsaturated iminium ions is slow in acetonitrile when only weakly basic counterions are present. When the reactions are carried out in the presence of KCF3CO2, fast deprotonation of the intermediate r-adducts occurs, and the rate constant for the rate-determining CC bond-forming step can be predicted from the electrophilicity parameter E of the iminium ion and the N and s parameters of the pyrroles

Crystal structure of (1S, 2R)-6,6-dimethyl-4,8-dioxo-2-phenylspiro[2.5] octane-1-carbaldehyde

In the title compound, C17H18O3, the two non-spiro C atoms of the cyclopropane ring bear a formyl and a phenyl substituent which are trans-oriented. In the crystal, molecules are linked by weak C-H center dot center dot center dot O and C-H center dot center dot center dot pi contacts resulting in a three-dimensional supramolecular structure

Kinetics and mechanism of organocatalytic aza-Michael additions: direct observation of enamine intermediates.

The imidazoles 1a–g add to the CC-double bond of the iminium ion 2 with rate constants as predicted by the equation log k = sN(N + E). Unfavourable proton shifts from the imidazolium unit to the enamine fragment in the adduct 3 account for the failure of imidazoles to take part in iminium-activated aza-Michael additions to enals

Crystal structure of 2-[chloro(4-methoxyphenyl)-methyl]-2-(4-methoxyphenyl)-5,5-dimethylcyclohexane-1,3-dione

In the title compound, C23H25ClO4, the cyclohexane ring adopts a chair conformation with the 4-methoxyphenyl substituent in an axial position and the chloro(4-methoxyphenyl) methyl substituent in an equatorial position. The packing features inversion dimers formed by pairs of C-H center dot center dot center dot O contacts and strands along [100] and [010] established by further C-H center dot center dot center dot O and C-H center dot center dot center dot Cl contacts, respectively

Organophosphorus Chemistry from a Physical Organic Chemist's Point of View

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Redox Catalysis for Radical Reactions: Synthetic and Mechanistic Aspects

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Mechanistically Driven Development of Carbon-Phosphorus Bond Forming Reactions

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Physical Organic Tools for Understanding Polar and Radical Reactions

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Physical Organic Tools for Understanding Polar and Radical Reactions, Jiangxi Normal University, China

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Physical Organic Tools for Understanding Polar and Radical Reactions,

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