Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
Science. 2013 Nov 29;342(6162):1080-3. doi: 10.1126/science.1244466.
A rational approach is needed to design hydrogenation catalysts that make use of Earth-abundant elements to replace the rare elements such as ruthenium, rhodium, and palladium that are traditionally used. Here, we validate a prior mechanistic hypothesis that partially saturated amine(imine)diphosphine ligands (P-NH-N-P) activate iron to catalyze the asymmetric reduction of the polar bonds of ketones and imines to valuable enantiopure alcohols and amines, with isopropanol as the hydrogen donor, at turnover frequencies as high as 200 per second at 28°C. We present a direct synthetic approach to enantiopure ligands of this type that takes advantage of the iron(lI) ion as a template. The catalytic mechanism is elucidated by the spectroscopic detection of iron hydride and amide intermediates.
需要采取合理的方法来设计氢化催化剂，利用丰富的地球元素替代传统上使用的钌、铑和钯等稀有元素。在这里，我们验证了一个先前的机理假设，即部分饱和的胺（亚胺）二膦配体（P-NH-N-P）激活铁来催化酮和亚胺的极性键的不对称还原，生成有价值的对映纯醇和胺，以异丙醇作为氢供体，在 28°C 时的周转频率高达每秒 200 次。我们提出了一种直接的合成方法，利用铁（II）离子作为模板来制备这种对映纯配体。通过光谱检测铁氢化物和酰胺中间体阐明了催化机理。
