THE TRAPPING OF 6,6-DIMETHYLISOBENZOFULVENE BY ITS 1,3-DIPOLAR PRECURSOR: A RARE EXAMPLE OF A DIPOLAR [6+4] CYCLOADDITION

Abstract

A new route to isobenzofuran and isobenzofulvene is reported that is proposed to involve the 14e electrocyclic fragmentation of a transient 1,3-dipolar intermediate formed by ring-opening of a fused aziridinocyclobutane. 6,6-Dimethylisobenzofulvene generated in this way reacts with its 1,3-dipole precursor to form a [10π+4π] cycloadduct, the first of this type involving the participation of a 1,3-dipolar species.

ACKNOWLEDGMENT

M.L.A.H. thanks the Center for Molecular Architecture for the award of an honors scholarship. This project was supported by funds from the CQU Merit Research Program. We thank Dr. Ian Pitt for performing the experiment involving the addition of isobenzofuran to 7-isopropylidenebenzonorbornadiene well ahead of its time (ANU, 14/9/82).