Premium
Chiral Modular n‐ Butyllithium Aggregates: n BuLi Complexes with Anisyl Fencholates
Author(s) -
Goldfuss Bernd,
Steigelmann Melanie,
Rominger Frank,
Urtel Heiko
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20011015)7:20<4456::aid-chem4456>3.0.co;2-s
Subject(s) - enantiopure drug , chemistry , benzaldehyde , butyllithium , stereochemistry , medicinal chemistry , molecule , crystallography , enantioselective synthesis , catalysis , organic chemistry
Chiral, enantiopure aggregates are formed spontaneously by mixing solutions of n ‐butyllithium with anisyl fenchols. X‐ray crystal analyses reveal the structures of these aggregates with different ortho substituents in the anisyl moieties (X), X=H ( 1‐H ), SiMe 3 ( 2‐H ), t Bu ( 3‐H ) SiMe 2 ( t Bu) ( 4‐H ) and Me ( 5‐H ). While the complex of 1‐BuLi shows a 3:1 composition, 2‐BuLi, 3‐BuLi and 4‐BuLi yield 2:2 stoichiometries. The aggregate 5‐BuLi crystallizes with a 2:4 composition and hence is a derivative of hexameric n‐ butyllithium, in which two trans ‐situated n BuLi molecules are substituted by lithium fencholate moieties. The variety in the synthesized chiral n BuLi aggregates demonstrates the high propensity of anisyl fencholates to chirally modify n BuLi. Variations in the modular ligand structures by alterations of the ortho ‐substituents (X) enable tunings of compositions and also of enantioselectivities in n BuLi additions to benzaldehyde.