References
- Freeman , P. K. and Hardy , T. A. 1971 . Tetrahedron Lett. , : 3939
- Baird , M. C. 1974 . Chem. Commun. , : 197 J. Chem. Soc., Perkin I, 1020 (1979)
- Winstein , S. , Ogliaruso , M. , Sakai , M. and Nicholson , J. M. 1967 . J. Am. Chem. Soc. , 89 : 3956 and references contained therein
- Johnson , T. H. and Cheng , S.-S . 1979 . J. Am. Chem. Soc. , 101 : 5277
- Volger , H. C. , Hogeveen , H. and Gaasbeek , M. M. P. 1969 . J. Am. Chem. Soc. , 91 : 2137
- Johnson , T. H. 1979 . J. Org. Chem. , 44 : 1356 and references contained therein
- Kottwitz , J. and Vorbruggen , H. 1975 . Synthesis , : 636
- We thank Professor M. C. Baird (The University of Newcastle upon Tyne) for a copy of his 1H NMR spectrum of 3