Synthesis and structures of some silylallyl-lithium or -potassium complexes

Abstract

The η³-1,3-bis(silyl)allyllithium [Li{η³-CH(CHSiMe₂Bu^t)(CHSiMe₂R)}(tmen)] (R = Bu^t or Me) and 1,3-bis(trimethylsilyl)cyclohexenyllithium [Li{C(SiMe₃)CHC(SiMe₃)(CH₂)₂CH₂}(tmen)] complexes were obtained by lithiation of the appropriate 1,3-bis(silyl)propene or 1,3-bis(trimethylsilyl)cyclohexene. The lithium complexes were transformed into the potassium complexes [K{CH(CHSiMe₂Bu^t)₂}] or [K{C(SiMe₃)CHC(SiMe₃)(CH₂)₂CH₂}] by reaction with KOBu^t. A dimethylsilyl ansa-bridged bis(cyclohexenyl)dipotassium complex [{K₂{(η³-C₆H₄SiMe₃-6)₂SiMe₂}(thf)₃}_∞] was obtained by a similar route. Single crystal structures of three complexes have been determined.