TADDOLate complexes of zinc

Abstract

TADDOL (α,α,α′,α′-Tetraaryl-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol) and its derivatives have been used as a chiral auxiliary in a huge number of enantioselective syntheses mediated by transition metals. Herein we report for the first time on the synthesis and structural characterization of Zn-TADDOLate complexes. The homo trinuclear zinc complex, [Me₂Zn₃{(S,S)-TADDOLate}₂(THF)₂], was obtained by reaction of TADDOL with dimethylzinc, whereas the hetero trinuclear complex, [Li₂Zn{(S,S)-TADDOLate}₂(THF)₂], was synthesized from dilithium TADDOLate with zinc dichloride. Both structures reveal a non-linear trimetallic M⋯Zn⋯M setup, which is surrounded by two TADDOLate ligands.