The chiral monoaza-15-crown-5 lariat ethers annellated to methyl-4,6-O-benzylidene-α-d-glucopyranoside-1 or mannopyranoside 2 have been applied as phase-transfercatalysts in the epoxidation of substituted chalcones and chalcone analogues with tert-butylhydroperoxide resulting in significant asymmetricinduction. It was found that the position of the substituents in the aromatic ring of the chalcone
Diaryl-2-pyrrolidinemethanols catalyzed enantioselective epoxidation of α,β-enones: new insight into the effect of structural modification of the catalyst on reaction efficiency
作者:Alessandra Lattanzi、Alessio Russo
DOI:10.1016/j.tet.2006.10.005
日期:2006.12
Catalytic enantioselectiveepoxidation of α,β-unsaturated ketones promoted by diaryl-2-pyrrolidinemethanols and tert-butyl hydroperoxide (TBHP) is described. Investigation on structural modifications of the diaryl-2-pyrrolidinemethanols showed that fine tuning of the stereoelectronics of the substituents on the aryl moiety is important to achieve high efficiency. By employing a structurally optimized
A highly efficient catalytic kinetic resolution of 2,3-epoxy 3-aryl ketones via asymmetric ring-opening with pyrazole derivatives has been achieved by using a chiral N,N′-dioxide–Sc(iii) complex as the catalyst.
Asymmetric Epoxidation oftrans-Chalcones Organocatalyzed by β-Amino Alcohols
作者:Alessio Russo、Alessandra Lattanzi
DOI:10.1002/ejoc.200800140
日期:2008.6
examined as organocatalysts in the epoxidation of trans-chalcones with tert-butyl hydroperoxide as the oxidant. Primary, secondary, and tertiary β-amino alcohols are able to promote the reaction with variable activity and level of asymmetric induction. Subtle modifications to the structures of simple primary β-amino alcohol strongly influenced their efficiency in the epoxidation. They are promising catalysts
Bis(3,5-dimethylphenyl)-(S)-pyrrolidin-2-ylmethanol: an Improved Organocatalyst for the Asymmetric Epoxidation of α,β-Enones
作者:Alessandra Lattanzi
DOI:10.1002/adsc.200505370
日期:2006.2
The asymmetricepoxidation of α,β-enones by the readily available bis(3,5-dimethylphenyl)-(S)-pyrrolidin-2-ylmethanol and tert-butyl hydroperoxide (TBHP) is described. Stereoelectronic substitution on the aryl moiety of diaryl-2-pyrrolidinemethanols was found to significantly affect the efficiency with respect to the previously reported (S)-diphenyl-2-pyrrolidinemethanol. Improved reactivity and enantioselectivity