Halogen-Bonding-Induced Conjugate Addition of Thiophenes to Enones and Enals.

Herein, we report the conjugate addition of α,β-unsaturated carbonyl compounds to thiophene derivatives. We used a 2-iodoimidazolinium triflate salt as a halogen-bonding donor, which afforded moderate-to-excellent yields of the corresponding alkylated thiophenes. Insight into the catalytic process was obtained from H NMR spectroscopy studies and DFT calculations, which indicated a halogen-bonding-supported mechanism with limited Brønsted acid catalysis.

Mechanism of Direct C-H Arylation of Pyridine via a Transient Activator Strategy: A Combined Computational and Experimental Study.

Recently, we realized the highly selective one-pot synthesis of 2,6-diarylpyridines by using a Pd-catalyzed direct C-H arylation approach via a transient activator strategy. Although methylation reagent as a transient activator and Cu(I) salt or oxide were found to be prerequisites, details regarding the mechanism remained unclear. In this paper, DFT calculations combined with experimental investigations were carried out to elucidate the principle features of this transformation.

Halogen-bonding-induced hydrogen transfer to C═N bond with Hantzsch ester.

Several bidentate dihydroimidazolines were prepared and investigated as catalysts for hydrogen transfer reduction of C═N bond with Hantzsch ester. Highly efficient reactions were observed for quinolines and imines with low catalyst loading of 2 mol %. The presence of halogen bonding was elucidated using NMR studies and isothermal calorimeric titrations.