Tetracyclone benzyne assay

Cyclic 1,3-dienes (with an inherent s-cis conformation) can react with benzyne to afford Diels-Alder adducts in high yields (Scheme 114). The addition to ftiran (228), reported by Wittig and Pohmer in 1955," is so efficient diat it has become a diagnostic test for die formation of benzyne. Cyclt nta-diene" and tetracyclone (492)" also serve as standard assay reagents. 

---