A Library of Chiral Imidazoline–Aminophenol Ligands: Discovery of an Efficient Reaction Sphere
作者:Takayoshi Arai、Naota Yokoyama、Akira Yanagisawa
DOI:10.1002/chem.200701439
日期:2008.2.27
ligands. Further reductive alkylation using salicylaldehydes 7-10 provided a series of imidazoline-aminophenol ligands (L9-L24). Analysis by solid-phase catalysis/circular dichroism high-throughput screening of a copper-catalyzed Henry reaction revealed that ligand L25, comprising a (S,S)-diphenylethylenediamine-derived imidazoline, (S)-phenylethylamine, and dibromophenol, was highly efficient, thus providing
Asymmetric Friedel–Crafts reaction of N-heterocycles and nitroalkenes catalyzed by imidazoline–aminophenol–Cu complex
作者:Naota Yokoyama、Takayoshi Arai
DOI:10.1039/b904275j
日期:——
Catalytic asymmetric FriedelâCrafts reaction of pyrrole with nitroalkenes was smoothly catalyzed by newly synthesized nitro-substituted imidazolineâaminophenol (1b)âCu complex to give the adduct with up to 92% ee.
Nitrogen-tethered bisimidazoline (Nb-imidazoline) ligand was utilized in the Cu(I)-catalyzed benzoylation of 1,2-diols. With the assistance of i-Pr(2)NEt, the reaction of rac-1,2-diols with o-methylbenzoyl chloride was smoothly catalyzed by Nb-imidazoline-CuCl in CH(2)Cl(2) to give the corresponding o-methylbenzoylated secondary alcohols in tip to 79% ee.