Alkyl Transfer from CC Cleavage

Abstract

Hydrogenation was only the beginning: Hantzsch esters have now been used to transfer alkyl groups to imines under mild catalytic conditions to provide a variety of amines (see scheme). Benzyl, secondary alkyl, and tertiary alkyl groups containing ether, ester, and hydroxy functionalities were transferred successfully. The use of Hantzsch esters as alkylation reagents offers a practical and complementary alternative to organometallic processes.

Anion‐Binding Catalysis by Electron‐Deficient Pyridinium Cations

“…Compounds of type 7 have recently been reported to transfer their C4 substituent to reactive electrophiles, albeit slowly and at temperatures above 100 8C. [18] However, the typical 1 H NMR resonances of compound 7 were not detectable under in situ monitoring conditions (200 K) and nor does isolated 7 undergo any transformation when exposed to the electrophile 1 a, even at room temperature for > 20 h. We therefore conclude that no covalent intermediate is involved in the catalytic cycle.…”

Hantzsch Ester as a Visible‐Light Photoredox Catalyst for Transition‐Metal‐Free Coupling of Arylhalides and Arylsulfinates

“…[2][3][4] 4-Alkyl-or acyl-Hantzsch esters can be used as alkyl and acyl radical precursors in CÀCf ormations. [5,6] Recently,t he excited-state of HEs have also been identified as strong photoreductants (E ox (*HEH) = À2.28 Vv s. SCE;H EH = 2,6-dimethyl-1,4dihydropyridine-3,5-dicarboxylate). [7a] Under photoirradiation, the excited HEs have acted as electron and hydride donors in the reduction of phenacyl onium salts, [8] debromination of alkyl bromides [7] and vicinal dibromo compounds, [9] reductive cleavage of the CÀPb ond in difluorinated phosphonium salts, [10] and reduction of cyanopyridines [11] and aryl tri-/ difluoroethanones.…”

Co(II) or Cu(II) Schiff Base Complex Immobilized onto Carbon Nanotubes as a Synergistic Catalyst for the Oxygen Reduction Reaction

“…[10] One-dimensional mesoporous Pt nanorods were effective as electrocatalysts for ORR. [11] Metal-Schiff base complexes immobilized onto supports showed good catalytic activity and stability in many organic synthesis reactions, including CÀC bonding formation, hydrogenation, hydroformylation, oxidation and epoxidation reactions. [12] Different from heterogeneous catalysts obtained by pyrolysis method, the heterogenization of molecular catalyst has definite and regular active sites, which favors the identification of catalytic active sites.…”