Enantioselective Hydrogenation of Ketones

由于现有的均相催化剂缺乏反应性和/或立体选择性，因此非常需要开发实现简单酮的立体选择性氢化的实用方法。一种新的Ru（II）配合物trans-RuCl_2 [（S）-xylbinap][（S）-daipen]或R，R对映体作为简单酮（XylBINAP=2，2 '-bis（di-3，5-xylylphosphino）-1，1'-binaphthyl）不对称氢化的预催化剂。DAIPEN=1，1-联茴香基-2-异丙基-1，2-乙二胺）。反应在室温下，在1-80 atm（大部分<10atm）的氢气气氛下，在含碱的异丙醇中，底物/催化剂摩尔比为10万的条件下进行。各种各样的前手性酮以高度的对映选择性氢化。开链α，β-不饱和酮在C=O键上选择性加氢得到高ee值的手性烯丙醇，解决了一个长期存在的合成难题。环丙基酮的氢化反应得到相应的 ...更多信息 ng甲醇在高ee无骨骼变化。具有各种取代基的烷基芳基酮以一致的高对映选择性氢化。2，2，2-三氟苯乙酮和环取代的衍生物也可用作底物。该反应对卤代芳烃和CF_3，OCH_2，COOCH（CH_3）_2，NO_2和NH_2基团都有耐受性。各种邻位取代的二苯甲酮被氢化为手性二苯甲醇，具有一致的高ee值。没有观察到过度还原形成二芳基甲烷。该催化剂体系对杂芳酮的不对称选择性加氢反应非常有效。含呋喃、噻吩、吡咯、噻唑或吡啶环的底物以相同的不对称方向氢化，得到具有一致高ee的手性仲醇。杂环的电子性质、刘易斯碱性倾向和空间尺寸对对映选择性的程度影响不大。由于催化剂成本低、操作简单和环保意识，该方法特别适用于大规模反应。少

The development of practical methods effecting stereoselective hydrogenation of simple ketones is highly desirable, since the existing homogeneous catalysts lack reactivity and/or stereoselectivity. A new Ru (II) complex, trans-RuCl_2 [(S)-xylbinap][(S)-daipen] or the R, R enantiomer acts as an excellent precatalyst for asymmetric hydrogenation of simple ketones (XylBINAP=2, 2'-bis (di-3, 5-xylylphosphino)-1, 1'-binaphthyl. DAIPEN=1, 1-dianisyl-2-isopropyl-1, 2-ethylenediamine). The reaction is conducted with a substrate/catalyst molar ratio of up to 100000 in 2-propanol containing alkaline base under 1-80 atm (mostly <10 atm) of H_2 at room temperature. A wide variety of prochiral ketones are hydrogenated with a high degree of enantioselection. Hydrogenation of open-chain α, β-unsaturated ketones proceeds selectively at the C=O linkage to afford chiral allylic alcohols with a high ee, solving a long-standing synthetic problem. Hydrogenation of cyclopropyl ketones gives the correspondi … More ng carbinols in high ee without skeletal change. Alkyl aryl ketones with various substituents are hydrogenated with a consistently high enantioselectivity. 2, 2, 2-Trifluoroacetophenone and the ring-substituted derivatives are also usable as substrates. The reaction is tolerant of aromatic halides and CF_3, OCH_2, COOCH(CH_3)_2, NO_2, and NH_2 groups. Various ortho-substituted benzophenones are hydrogenated to chiral benzhydrols with consistently high ee. No over-reduction forming to diarylmethanes are observed. The catalyst system is extremely effective for enantioselective hydrogenation of hetero-aromatic ketones. The substrates with furan, thiophene, pyrrole, thiazole, or pyridine rings are hydrogenated with the same asymmetric sense to give chiral secondary alcohols in consistently high ee. The electronic properties, Lewis basic tendency, and steric size of the heterocycles appear to have little effect on the extent of enantioselectivity. This procedure is particularly useful for a large-scale reaction because of the low cost of the catalyst, operational simplicity, and environmental consciousness. Less