We
report the first general and practical method for the addition
of aryl halides and alkynes to norbornenes with palladium catalysis.
Norbornenes have been used as the unsaturated acceptors of aryl and
alkynyl groups to construct saturated bridged C–C bonds. The
combination of Pd(OAc)2/PCy3HBF4 has
been identified as the optimal system promoting difunctionalization
of norbornenes via the C–X/C–H bond cleavage and highly
selective C(sp3)–C(sp2)/C(sp3)–C(sp) bond formation. Broad substrate scope and excellent
functional group tolerance have been achieved to show the high efficiency
of this approach. Mechanism studies based on experiments and DFT have
been performed to gain insights into the catalytic mechanism.