Intramolecular Hydroamination/Cyclization of Conjugated Aminodienes Catalyzed by Organolanthanide Complexes. Scope, Diastereo- and Enantioselectivity, and Reaction Mechanism
作者:Sukwon Hong、Amber M. Kawaoka、Tobin J. Marks
DOI:10.1021/ja036266y
日期:2003.12.1
precatalysts for the rapid, regioselective, and highly diastereoselective intramolecular hydroamination/cyclization of primary and secondary amines tethered to conjugated dienes. The rates of aminodiene cyclizations are significantly more rapid than those of the corresponding aminoalkenes. This dienyl group rate enhancement as well as substituent group (R) effects on turnover frequencies is consistent with
一般类型的有机镧系元素配合物 Cp'(2)LnCH(TMS)(2) (Cp' = eta(5)-Me(5)C(5); Ln = La, Sm, Y; TMS = SiMe(3) ) 和 CGCSmN(TMS)(2) (CGC = Me(2)Si(eta(5)-Me(4)C(5))((t)()BuN)) 作为快速、区域选择性的有效预催化剂,以及与共轭二烯相连的伯胺和仲胺的高度非对映选择性分子内加氢胺化/环化。氨基二烯环化的速度明显快于相应的氨基烯烃。这种二烯基速率增强以及取代基 (R) 对转换频率的影响与提议的过渡态电子需求一致。动力学和机械数据平行单取代氨基烯烃加氢胺化/环化,转换限制 C=C 插入 Ln-N 键,可能形成 Ln-eta(3) 烯丙基中间体,然后快速质子分解所得 Ln-C 键。速率定律在[催化剂]中是一级的,在[氨基二烯]中是零级的。然而,根据特定的底物和催化剂组合,与零级