Mechanistic investigations of the asymmetric hydrosilylation of ketimines with trichlorosilane reveals a dual activation model and an organocatalyst with enhanced efficiency
作者:X. Li、A. T. Reeder、F. Torri、H. Adams、S. Jones
DOI:10.1039/c6ob02537d
日期:——
Structural probes used to help elucidate mechanistic information of the organocatalyzed asymmetricketimine hydrosilylation have revealed a new catalyst with unprecedented catalytic activity, maintaining adequate performance at 0.01 mol% loading. A new ‘dual activation’ model has been proposed that relies on the presence of both a Lewis basic and Brønstedacidic site within the catalyst architecture
agent in the presence of a chiral Lewis base. The absolute configuration of the key intermediate was unambiguously assigned by X-ray analysis. The synthesis was also investigated exploiting continuous flow reactions; that is, an advanced intermediate of the target molecule was synthesized in only two in-flow synthetic modules, avoiding isolation and purifications of intermediates, leading to the isolation
已经分批研究了一种立体选择性合成策略,用于制备三氟甲胺模拟物的三氟甲胺模拟物,涉及非对映选择性、无金属催化步骤,并以良好的收率和高非对映选择性提供目标分子。合成顺序的一个关键点是在手性路易斯碱的存在下用三氯硅烷作为还原剂催化还原氟化烯胺。通过 X 射线分析明确指定了关键中间体的绝对构型。还研究了利用连续流动反应的合成;也就是说,目标分子的高级中间体仅在两个流入合成模块中合成,避免了中间体的分离和纯化,