Iron-Catalyzed Highly Enantioselective Hydrogenation of Alkenes
作者:Peng Lu、Xiang Ren、Haofeng Xu、Dongpo Lu、Yufeng Sun、Zhan Lu
DOI:10.1021/jacs.1c04773
日期:2021.8.18
for the first time an iron-catalyzed highlyenantioselectivehydrogenation of minimally functionalized 1,1-disubstituted alkenes to accesschiral alkanes with full conversion and excellent ee. A novel chiral 8-oxazoline iminoquinoline ligand and its iron complex have been designed and synthesized. This protocol is operationally simple by using 1 atm of hydrogen gas and shows good functional group tolerance
Enantioselective Synthesis of Chiral Sulfones by Rh-Catalyzed Asymmetric Addition of Boronic Acids to α,β-Unsaturated 2-Pyridyl Sulfones
作者:Pablo Mauleón、Inés Alonso、Marta Rodríguez Rivero、Juan C. Carretero
DOI:10.1021/jo7016197
日期:2007.12.1
calculations of the aryl−rhodium insertion step. These calculations strongly support the formation of a five-membered pyridyl−rhodium chelated species as the most stable complex after the insertion into the CC bond. These highly enantioenriched chiral sulfones are very appealing building blocks in enantioselective synthesis. For instance, the straightforward elimination of the 2-pyridylsulfonyl group by either
描述了将有机硼酸铑催化对映体选择性催化共轭加成至α,β-不饱和砜的一般有效方法。该方法的成功依赖于使用α,β-不饱和2-吡啶基砜作为关键的金属配位底物。典型的砜,例如乙烯基苯基砜在反应条件下是惰性的。在多种手性配体中,Chiraphos提供了最佳的不对称诱导。铑[Rh(acac)(C 2 H 4)2 ] / Chiraphos催化剂体系具有广泛的适用范围,适用于将芳基和烯基硼酸都添加到顺式和反式α,β-不饱和2-吡啶基砜。在大多数情况下,尤其是在添加芳基硼酸的情况下,反应可以干净且高对映选择性地进行,以高收率和对映选择性(70-92%ee)提供手性β-取代的2-吡啶基砜。通过对芳基-铑插入步骤的DFT理论计算已经研究了这种对映选择性的意义和大小。这些计算有力地支持了五元吡啶基-铑螯合物质的形成,这是插入到C中后最稳定的络合物。C键。这些高度对映体富集的手性砜是对映体选择性合成中非常有吸引力
Enantioselective Nickel-Catalyzed Cross-Coupling Reactions of Trialkynylindium Reagents with Racemic Secondary Benzyl Bromides
作者:Jorge Caeiro、José Pérez Sestelo、Luis A. Sarandeses
DOI:10.1002/chem.200701035
日期:2008.1.7
first enantioselective sp-sp3 cross-coupling reaction between alkynyl organometals and racemic benzylbromides is reported. The coupling is performed at room temperature by using NiBr2diglyme and (S)-(iPr)-Pybox as the catalytic system and trialkynylindium reagents as nucleophiles. The reaction is stereoconvergent, both enantiomers of the racemic benzylbromide are converted into one enantiomer of the
Iridium-Catalyzed Asymmetric Transfer Hydrogenation of 1-Aryl-1-alkylethenes with Ethanol
作者:Xixia Tang、Lu Qian、Guixia Liu、Zheng Huang
DOI:10.1021/acs.orglett.3c01880
日期:2023.7.7
Asymmetric transfer hydrogenation of 1-aryl-1-alkylethenes with ethanol was developed with a chiral (PCN)Ir complex as the precatalyst, featuring high enantioselectivities, good functional group tolerance, and operational simplicity. The method is further applied to formal intramolecular asymmetric transfer hydrogenation of alkenols without an external H-donor, producing a tertiary stereocenter and
以手性(PCN)Ir配合物为预催化剂,开发了1-芳基-1-烷基乙烯与乙醇的不对称转移氢化反应,具有对映选择性高、官能团耐受性好、操作简单等特点。该方法进一步应用于无需外部氢供体的烯醇的正式分子内不对称转移氢化,同时产生叔立构中心和远程酮基。克级合成和( R )-黄根醇关键前体的合成凸显了催化系统的实用性。
Catalytic Asymmetric Conjugate Reduction of β,β-Disubstituted α,β-Unsaturated Sulfones
作者:Tomás Llamas、Ramón Gómez Arrayás、Juan C. Carretero