Unconventional Site Selectivity in Palladium-Catalyzed Cross-Couplings of Dichloroheteroarenes under Ligand-Controlled and Ligand-Free Systems.

ABSTRACT: Halides adjacent to nitrogen are conventionally more reactive in Pd-catalyzed cross-couplings of dihalogenated N-heteroarenes. However, a very sterically hindered N-heterocyclic carbene ligand is shown to promote room-temperature cross-coupling at C4 of 2,4-dichloropyridines with high selectivity (∼10:1). This work represents the first highly selective method with a broad scope for C4-coupling of these substrates where selectivity is clearly under ligand control. Under the optimized conditions, diverse substituted 2,4-dichloropyridines and related compounds undergo cross-coupling to form C4-C_(sp2) and C4-C_(sp3) bonds using organoboron, -zinc, and -magnesium reagents. The synthetic utility of this method is highlighted in multistep syntheses that combine

SUBMITTER: Norman JP 

PROVIDER: S-EPMC9202362 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature