Selective Synthesis of Functional Alkynylmono- and -trisilanes

The selective synthesis of functional alkynylsilanes RC C(SiMe2)(m)-X (m = 1, 3) was investigated. Monofunctionalization with or without protecting groups gave moderate to good yields of alkynyldimethylmonosilanes RC CMe2SiX [R = Ph, X = Cl (1), NEt2 (2), OMe (3), H (4), Br (5), I (6), Cp (8), C5H4Li (10), Ph (11); R = Pr, X = Ph (12)]. Compounds 4 and 8 were converted into the (alkyne) transition-metal complexes 4 center dot Cp2Mo2(CO)(4) (13) and 8 center dot Co-2(CO)(6) (14), respectively, which were characterized by X-ray diffraction. Stepwise extension and functionalization of the silane chain starting from 1-chloro-2-(diethylamino)tetramethyldisilane (Et2NMe2Si-Si-Me2Cl) yielded the trisilanes Ph-(SiMe2)(3)-X [X = NEt2 (18), OMe (19), Cl (20), H (21), C CPh (22), C CPr (23)]. The synthesized compounds were characterized by NMR and IR spectroscopy, 4, 11, 13, and 14 also by UV/Vis spectroscopy.