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.