Insights into the Heck-Type Arylation of 1,2-Dihydropyridines: Site- and Regioselective Access to 2,3-Disubstituted Dihydropyridines

We report a site- and regioselective Heck-type arylation reaction for the synthesis of substituted 1,2-dihydropyridines from simple pyridine precursors. This transformation serves as a key step in our previously developed stepwise dearomative multi-functionalization platform, enabling the syn -addition of aryl halides to dihydropyridine intermediates under mild conditions. Comprehensive scope studies demonstrate broad functional group tolerance, accommodating both electron-rich and electron-deficient aryl iodides, a variety of N -protecting groups, and diverse C2 substituents.