Ligand-Induced chemodivergent nickel-catalyzed annulations via tandem isomerization/esterification and direct O-allylic substitution: Divergent access to 3,4-dihydrocoumarins and 2H-chromenes

Herein, we report unprecedented Ni-catalyzed chemodivergent annulations to produce the 3,4-dihydrocoumarins and 2H-chromenes that are important attractive building blocks in many biologically active compounds. By the introduction of dcype ligand, a range of 3,4-dihydrocoumarins can be afforded with good to excellent yield and wide functional group tolerance via chemoselective intramolecular tandem isomerization/esterification. In the absence of ligand, a useful synthesis of 2H-chromenes has been developed through a nickel-catalyzed direct O-allylic substitution with good to excellent efficiency.