s, 9H, CHltBu), 0.16 (5, 9H, SiMe,); "C-NMR (CDCL, -30°C): 6=107.7, 105.9 (s, je 1 C, BCB, breit), 42.0 (t, IC, CH3, 31.0 (s, IC, CH2-CMe3), 29.4 (q. 6C, B-CMe3), 29.2 (q, 3C, CH2-CMe3), 18.9 (s, 2C, BCMe,, breit), 1.2 (9, 6 C , SiMe,); MS (27 eV): m/z 304 ( M + , 64%). 247 (M+ -rBu. loo%), 73 (SiMef, 33%). -2d: farblose Kristalle, Subl.