Oxidation of nicotine in the presence of rabbit liver 10,000 x g supernatant, NADPH, and cyanide results in the production of 5’-cyanonicotine. NaBDl reduction of the reaction mixture from a similar incubation of nicotine, NADPH, and supernatant results in the production of deuteronicotine having a single deuterium in the pyrrolidine ring. Oxidation of nicotine to cotinine under 1802 did not le...

Electrophilic substitution of pyrroles by α,β-unsaturated iminium ions is slow in acetonitrile when only weakly basic counterions are present. When the reactions are carried out in the presence of KCF(3)CO(2), fast deprotonation of the intermediate σ-adducts occurs, and the rate constant for the rate-determining CC bond-forming step can be predicted from the electrophilicity parameter E of the ...

Metal complexes of meso-arylporphyrins (Cr(III), Fe(III), and Zn(II)) were evaluated in the coupling reaction of cyclohexene oxide (CHO) with CO2 in compressed medium, where the Cr complexes were demonstrated to be the most active systems, leading predominantly to copolymerisation products. It is noteworthy that no addition of solvent was required. To improve the catalytic activity, and to simu...

Class I fructose-1,6-bisphosphate aldolases catalyze the interconversion between the enamine and iminium covalent enzymatic intermediates by stereospecific exchange of the pro(S) proton of the dihydroxyacetone-phosphate C3 carbon, an obligatory reaction step during substrate cleavage. To investigate the mechanism of stereospecific proton exchange, high resolution crystal structures of native an...

Herein, we report a general iminium ion-based catalytic method for the enantioselective conjugate addition of carbon-centered radicals to aliphatic and aromatic enals. The process uses an organic photoredox catalyst, which absorbs blue light generate from stable precursors, in combination with chiral amine secures consistently high level stereoselectivity. generality this platform is demonstrat...

A straightforward synthesis of substituted 1,2-dihydroquinazolinium triflates (3) is reported by reaction of 2-imino-substituted anilines with a range of carbonyl compounds in the presence of triflic acid via intermediate iminium salts. Similar reactions with di- or trialdehydes and triflic acid give bis- or tris-(1,2-dihydroquinazolinium) salts. Some 4-methyl substituted 1,2-dihydroquinazolini...

Over the last 8 years, our laboratory has developed the concept of iminium catalysis, a mode of LUMO-lowering activation that has enabled the invention of a large number of enantioselective organocatalytic transformations including Diels-Alder cycloadditions, Friedel-Crafts alkylations, Mukaiyama-Michael additions, hydrogenations, and heteroconjugate additions.1 Central to the utility of this t...

The title compound, C(17)H(16)N(4)O(6), is a Schiff base, which is found as a bis-zwitterion in the solid state. The geometry around the iminium N atom indicates sp(2)-hybridization. The diiminiumpropyl-ene chain is in an approximate double-gauche conformation, with average N-C-C-C torsion angles of 69.3°. The zwitterion shows strong intra-molecular N-H⋯O hydrogen bonds between the iminium N an...

The first reported examples of kinetic resolution in epoxidation reactions using iminium salt catalysis are described, providing up to 99% ee in the epoxidation of racemic cis-chromenes.