1. P. Bladon and D. R. Rae,J. Chem. Soc., Perkin Trans, 1, 1974, 2240.
2. P. Bladon and D. R. Rae,J. Chem. Soc., Perkin Trans. 1, 1975, 2460.
3. Yu. V. Tomilov, E. V. Shulishov, and O. M. Nefedov,Izv. Akad. Nauk SSSR, Ser. Khim., 1991, 1057 [Bull. Acad. Sci. USSR, Div. Chem. Sci., 1991,40, 939 (Engl. Transl.)].
4. C. J. Rostek and W. M. Jones,Tetrahedron Lett., 1969, 3957.
5. L. Fitjer and J. M. Conia,Angew. Chem.,1973, 85, 349.