17557-10-7Relevant articles and documents
α-Lithium Alkyls of α-Trimethylsilyl-p-xylenes and the Synthesis of p-C6H4(CH2SnMe3)2 from a New Di-Grignard Reagent: Crystal Stucture of 2>
Leung, Wing-Por,Raston, Colin L.,Skelton, Brian W.,White, Allan H.
, p. 1801 - 1808 (2007/10/02)
Metallation of the p-xylene compounds p-C6H4(CHRR')(CHR''R''') (R,R',R'',R'''=H or SiMe3) with n(tmen)> (tmen=NNN'N'-tetramethylethylenediamine) or n(pmdien)> (pmdien=NNN'N''N''-pentamethyldiethylenetriamine) occurs selectively at the benzylic carbon atom(s) (Cα) in a manner dependent on the degree of substitution and the tertiary amine.Four of the organolithium complexes generated have been isolated as crystalline solids and the molecular structure of one, 2>, has been determined from single-crystal X-ray diffraction data.The p-xylenediyl moiety is planar with the trimethylsilyl groups trans to each other, being related by an inversion centre.There is evidence of a dominant p-quinodimethanide bonding contribution, with each lithium, on opposite sides of the C8H6Si2 plane, interacting unsymmetrically with both Cα and its adjacent ring-carbon atom α 2.10(1) and Li-Cβ 2.38(1) Angstroem>.A high-yield synthesis of a di-Grignard reagent derived from 1,4-bis(chloromethyl)benzene in thf (tetrahydrofuran) which yields a compound of composition n after ca. 1 h is described.The utility of this compound is illustrated by the synthesis of p-C6H4(CH2SnMe3)2 from SnMe3Cl.
