Chiral modular n-butyllithium aggregates: nBuLi complexes with anisyl fencholates

Chiral enantiopure aggregates are formed spontaneously by mixing solutions of n-butyllithium with anisyl fenchols. X-ray crystal analyses reveal the s tructures of these aggregates with different ortho substituents in the anis yl moieties (X), X = H (1-H), SiMe3 (2-H), tBu (3-H) SiMe2(tBu) (4-H) and M e (5-H). While the complex of 1-BuLi shows a 3:1 composition, 2-BuLi. 3-BuL i and 4-BuLi yield 2,2 stoichiometries. The aggregate 5-BuLi crystallizes w ith a 2:4 composition and hence is a derivative of hexameric n-butyllithium , in which two trans-situated nBuLi molecules are substituted by lithium fe ncholate moieties. The variety in the synthesized chiral nBuLi aggregates d emonstrates the high propensity of anisyl fencholates to chirally modify nB uLi. Variations in the modular ligand structures by alterations of the orth o-substituents (X) enable tunings of compositions and also of enantioselect ivities in nBuLi additions to benzaldehyde.