Asymmetric Catalytic Intramolecular Hydroamination of Aminoallenes by Tantalum Amidoalkoxide Complexes
作者:Michelle C. Hansen、Carolyn A. Heusser、Tarun C. Narayan、Kristine E. Fong、Nagiko Hara、Alexander W. Kohn、Alexander R. Venning、Arnold L. Rheingold、Adam R. Johnson
DOI:10.1021/om200446v
日期:2011.9.12
monomeric with an approximate trigonal-bipyramidal geometry. The resulting complexes were examined for their in situ activity for catalytic asymmetric hydroamination/cyclization of an aminoallene. Enantioselectivities up to 80% ee were observed for the cyclization of 6-methylhepta-4,5-dienylamine to 2-(2-methylpropenyl)pyrrolidine at 135 °C with 5 mol % catalyst loading.
制备了一系列手性双齿氨基烷氧化物配体的钽配合物。得到一种配合物Ta(NMe 2)3 [-OCPh 2 CH(CHMe 2)N(c -C 6 H 11)-]的晶体结构。不同于先前描述的具有这些配体的钛配合物,它们与桥连的氧原子二聚,该钽配合物是具有近似三角-双锥体几何结构的单体。检查所得复合物的原位活性用于氨基丙烯的不对称催化氨化/环化反应。在135℃下以5 mol%的催化剂负载量,将6-甲基庚-4,5-二烯基胺环化为2-(2-甲基丙烯基)吡咯烷,观察到高达80%ee的对映选择性。