Annulation selectivity in the coupling of Fischer carbene complexes with o-alkynylbiphenyl and o-alkynylstyrene derivatives

The coupling of various Fischer carbene complexes with o-ethynylbiphenyl and an o-alkynylstyrene derivatives has been examined. In coupling reactions with methylcarbene and cyclopropylcarbene complexes, the major products are derived from C–H or C–C activation processes. In coupling reactions with phenylcarbene complexes, the major products are derived from the Dötz reaction.