Carbaborane Syntheses, Interconversions, and Reactions

3- vinyl-o-carbaborane gi ws good yields of 1,2-dibromoethyl-o-carbaborane, which on dehydrobromination with NaNHa in liquid ammonia gives 3-ethynyl-o-carbaborane. Pyrolysis of these products yields respectively 2- and 

4- vinyl(ethynyl)-m-carbaboranes. Bromination of o-carbaborane in trifluorace-tic acid yields an expedient synthesis of 9(12 bromo-o-carbaborane. The reaction of icosahedral carbaboranes with excess sulphur over AICI3 converts o-carbaborane to 9,12- and m-carbaborane to 9,10- and 5(4), 9-dithiols in high yields. Treatment of these with CHjBra yields cyclic thioforraal derivatives. Reaction of 9,12-(HS)8-l,2-C9BioHio with acetone and AICI3 alfords a cyclic thioketal. These new derivatives are all characterized by H- B n.m.r. and mass spectrometry.  

Kukina, M. A. Porai-Koshits, V. S. Sergienko, O. Strouf, K. Base, I. A. Zakharova, and B. Stibr, Izv. Akad, Nauk SSSR, Ser. Khim., 1980, 1686. 

Plesek, Z. Janousek, and S. Hermanek, Collect. Czech. Chem. Common., 1980, 45, 1775. 

Drygina, G. N. Dorofeenko, and O. Yu. Okhlobystin, Izv. Sev.-Kavk. Nauchn. Tsentra Vyssh. Shk., Estestv. Nauki, 1980, 53. 

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