Mai Enzo, Schneider Christoph
Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany.
Chemistry. 2007;13(9):2729-41. doi: 10.1002/chem.200601307.
The scandium-bipyridine-catalyzed enantioselective 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 catalyst loading may be lowered to just 5 mol% with only marginal effects on yield and enantioselectivity. A strong positive nonlinear effect has been observed, pointing to aggregation phenomena of the catalyst.
钪-联吡啶催化的苯胺和O-烷基羟胺对内消旋环氧化合物的对映选择性加成反应已得到优化,并扩展到了多种环氧化合物和胺类。虽然芳香族内消旋环氧化合物通常能以优异的对映选择性得到相应的1,2-氨基醇,但脂肪族内消旋环氧化合物在氨解反应中仅产生中等的对映选择性。催化剂负载量可降低至仅5 mol%,而对产率和对映选择性仅有微小影响。观察到了强烈的正非线性效应,这表明催化剂存在聚集现象。