Manganese-Catalyzed Divergent Markovnikov Addition and [2+2+2] Cycloaddition of 2‑Carbonyl Indanone with Terminal Alkyne

Herein, we report on manganese-catalyzed
regioselective Markovnikov
addition and [2+2+2] cycloaddition of 2-carbonyl indanones with terminal
alkynes. This method provides an efficient approach for the construction
of all-carbon quaternary centers and complex polycyclic hydrocarbon
frameworks by the formation of new carbon–carbon single bonds
in a regio- and stereoselective manner. Preliminary mechanistic experiments
involving deuterium labeling, kinetic, catalytic, and stoichiometric
reactions with plausible intermediates were performed to shed light
on the reaction mechanism.