Generation and Trapping of Isobenzofuran Intermediates Formed in the Coupling of Fischer Carbene Complexes and o-Alkynylbenzoyl Derivatives

[formula: see text] The coupling of o-alkynylbenzoyl derivatives with carbene complexes has been investigated. The reaction initially affords isobenzofuran derivatives, which convert to alkylidenephthalan derivatives or can be trapped by various dienophiles to afford benzo-oxanorbornene derivatives.