• Treatment of phthalan with excess Li metal in the presence of 4,4'-Di-tert-butylbiphenyl, B21470, results in opening of the furan ring. Sequential introduction of two different electrophiles can be effected in the resulting bis-benzylic species, consequently phthalan can be regarded as an o-xylene dianion synthon. This approach provides a convenient access to diols and hydroxy acids which can be readily dehydrated to benzo-fused 6- or 7-membered cyclic ethers or lactones: Tetrahedron, 51, 3351 (1995); see also: J. Org. Chem., 61, 4913 (1996); Tetrahedron Lett., 39, 7759 (1998).
• For use in synthesis of nine-membered cyclic dione ethers, see: Synlett, 909 (1993).