References
- Wegner , G. 1972 . Makromol. Chem. , 154 : 35
- Schermann , W. and Wegner , G. 1975 . J. Polymer Sci., Part B , 13 : 753
- Wegner , G. 1971 . J. Polymer Sci. Part B , 9 : 133
- Malthetc , J. 1973 . Mol. Cryst. and Liq. Cryst. , 23 : 233
- Cox , R. J. and Clecak , N. J. 1976 . Mol. Cryst. and Liq. Cryst. , 37 : 241
- Barrall , E. M. II , Grant , B. D. and Gregges , A. R. in press.
- Eglinton , G. and McCrae , W. 1963 . Advances in Organic Chemistry , Edited by: Raphael , R. A. , Taylor , E. C. and Wynberg , H. Vol. 4 , New York : Interscience Pub. .
- Corey , E. J. and Fuchs , P. L. 1972 . Tetrahedron Lett. , 3769
- Fritzshe , U. and Hunig , S. 1972 . Tetrahedron Lett. , 4831
- Kotlyarevskii , I. L. and Bavdamova , M. I. 1964 . Izu. Akad. Nauk. SSSR, Ser. Khim. , 11 : 2073 Chem. Abstr., 62, 7665h (1965).
- Kataoka , M. , Ando , T. and Nakagawa , M. 1971 . Bull. Chem. Soc. Jap. , 44 : 1909
- von Albrecht Franke , Mattern , G. and Traber , W. 1975 . Helv. Chem. Acta. , 58 : 278 It has been observed previously (P. L. Fuchs, private communication) that acetal protecting groups are not stable to the conditions for preparation of the β,β-dibromoolefins, using an excess of triphenyl phosphine (Method A8). The reaction can be successfully effected in the presence of acetal groups if zinc powder is used as the bromine scavenger (Method B8). There appears to be a discrepancy between the melting point reported in the original report10 of 215[ddot]C and that recorded in the abstract10 of 222[ddot]C. Satisfactory analytical data were obtained for all new compounds listed in Figures 1 and 2. The higher boiling olefins were occasionally contaminated with small amounts of triphenylphosphine oxide. This impurity did not interfere with the subsequent reaction.