Huo Shangfei, Wang Qingwei, Zuo Weiwei
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of materials science and engineering, Donghua University, China.
Dalton Trans. 2020 Jun 21;49(23):7959-7967. doi: 10.1039/d0dt01204a. Epub 2020 Jun 4.
We report the design of a new iron catalyst for the asymmetric transfer hydrogenation of ketones. This type of iron catalyst combines the structural characteristics of the Noyori hydrogenation catalyst (an axially chiral 2,2'-bis(phosphino)-1,1'-binaphthyl fragment and the metal-ligand bifunctional motif) and an ene(amido) group that can activate the iron center. After activation by 8 equivalents of potassium tert-butoxide, (S,R,SS)-7a and (S,R,SS)-7b are active but nonenantioselective catalysts for the transfer hydrogenation of acetophenone and α,β-unsaturated aldehydes at room temperature in isopropanol. A maximum turnover number of 14480 was observed for (S,R,SS)-7a in the reduction of acetophenone. The right combination of the stereochemistry of the axially chiral 2,2'-bis(phosphino)-1,1'-binaphthyl group and the carbon-centered chiral amine-imine moiety in (S,R,RR)-7b' afforded an enantioselective catalyst for the preparation of chiral alcohols with moderate to good yields and a broad functional group tolerance.
我们报道了一种用于酮不对称转移氢化的新型铁催化剂的设计。这种类型的铁催化剂结合了诺伊里氢化催化剂的结构特征（一个轴向手性的2,2'-双（膦基）-1,1'-联萘片段和金属-配体双功能 motif）以及一个可以活化铁中心的烯（酰胺）基团。用8当量叔丁醇钾活化后，(S,R,SS)-7a和(S,R,SS)-7b在室温下于异丙醇中对苯乙酮和α,β-不饱和醛的转移氢化是有活性但非对映选择性的催化剂。在苯乙酮的还原反应中，(S,R,SS)-7a的最大周转数为14480。(S,R,RR)-7b'中轴向手性的2,2'-双（膦基）-1,1'-联萘基团的立体化学与以碳为中心的手性胺-亚胺部分的正确组合，提供了一种用于制备手性醇的对映选择性催化剂，产率适中至良好，且对官能团具有广泛的耐受性。
