1. For a review see: E.N. Marvell and T. Li, Synthesis, 1973, 457.
2. A. Farkas, Trans. Faraday Soc., 35, 906 (1939).
3. Cf. LS. Zalkind, Zh. Fiz. Khim, 52, 191 (1920)
4. Cf. LS. Zalkind, Chem. Abstr., 17, 1453 (1923)
5. M. Bourguel and V. Gredy, C. R. Acad. Sci., Ser. C, 189, 757 (1929)