Asymmetric Cu-Catalyzed 1,4-Dearomatization of Pyridines and Pyridazines without Preactivation of the Heterocycle or Nucleophile

We
show that a chiral copper hydride (CuH) complex catalyzes C–C
bond-forming dearomatization of pyridines and pyridazines at room
temperature. The catalytic reaction operates directly on free heterocycles
and generates the nucleophiles in situ, eliminating
the need for stoichiometric preactivation of either reaction partner;
further, it is one of very few methods available for the enantioselective
1,4-dearomatization of heteroarenes. Combining the dearomatization
with facile derivatization steps enables one-pot syntheses of enantioenriched
pyridines and piperidines.