Indium-Bipyridine Catalyzed, Enantioselective Aminolysis of <i>meso</i>-Epoxides
作者:Christoph Schneider、Enzo Mai
DOI:10.1055/s-2007-984902
日期:——
The scandium-bipyridine-catalyzedenantioselective addition of anilines and O-alkyl hydroxylamines to meso-epoxides has been optimized and extended to a broad range of epoxides and amines. Whereas aromatic meso-epoxides generally furnished the corresponding 1,2-amino alcohols in excellent enantioselectivities, aliphatic meso-epoxides only gave rise to moderate enantioselectivities in the aminolysis
The catalytic asymmetric ring opening of meso-epoxides with aromatic amines was achieved using a new proline-basedN,N′-dioxide-indiumtris(triflate) complex in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee) under mild conditions. The coordination ability of N,N′-dioxide 1c was investigated by X-ray and NMR analysis. A plausible seven-coordinate transition state model was
The scandium-bipyridine-catalyzedenantioselective addition of anilines and O-alkyl hydroxylamines to meso-epoxides has been optimized and extended to a broad range of epoxides and amines. Whereas aromatic meso-epoxides generally furnished the corresponding 1,2-amino alcohols in excellent enantioselectivities, aliphatic meso-epoxides only gave rise to moderate enantioselectivities in the aminolysis
Thieme Chemistry Journal Awardees - Where Are They Now? Bifunctional Organocatalysis with N-Formyl-l-Proline: A Novel Approach to Epoxide Ring Opening and Sulfide Oxidation
A conceptually distinct approach to the aminolysis of 1,2-epoxides, which involves Lewis base-Brønsted acid catalysis employing N-formyl-l-proline as an easily accessible bifunctional organocatalyst and water as a solvent is presented. The potential of N-formyl-l-proline as organocatalyst for the sulfide oxidation reaction using aqueous hydrogen peroxide as environmentally benign and readily available oxidant is also demonstrated. Good to high yields are achieved for both reactions.
A newly designed ligand with the bipyridine scaffold (an analog of Bolm's ligand), in combination with Sc(OTf)3, exhibits high stereocontrol in the ring opening of meso‐epoxides with various alcohols providing 1,2‐alkoxyalcohols.