A Copper-Catalyzed Domino Route toward Purine-Fused Tricyclic Derivatives

Purine-fused
tricyclic derivatives have been synthesized via a
copper-catalyzed domino Michael/oxidative cross-coupling reaction
between adenines and nitroolefins for the first time. With air as
the oxidant, this method has high regioselectivity, which provides
a new route for constructing purine-nucleoside-conjugated systems
with two newly formed C–N bonds. Meanwhile, purine nucleosides
with an exocyclic amino group could be obtained easily by simple reduction,
which may lead to potential applications in fluorescence recognition
of various bases in vivo.