Mizoroki–Heck Cyclizations of Amide Derivatives for the Introduction of Quaternary Centers
作者:Jose M. Medina、Jesus Moreno、Sophie Racine、Shuaijing Du、Neil K. Garg
DOI:10.1002/anie.201703174
日期:2017.6
report non-decarbonylative Mizoroki–Heck reactions of amide derivatives. The transformation relies on the use of nickel catalysis and proceeds using sterically hindered tri- and tetrasubstituted olefins to give products containing quaternary centers. The resulting polycyclic or spirocyclic products can be obtained in good yields. Moreover, a diastereoselective variant of this method gives access to an
Asymmetric Aza-Wacker-Type Cyclization of <i>N</i>-Ts Hydrazine-Tethered Tetrasubstituted Olefins: Synthesis of Pyrazolines Bearing One Quaternary or Two Vicinal Stereocenters
aza-Wacker-type cyclization of N-Ts hydrazine-tethered tetrasubstituted olefins, affording optically active pyrazolines bearing chiral tetrasubstituted carbon stereocenters. This reaction is tolerant to a broad range of substrates under mild reaction conditions, giving the desired chiral products with high enantioselectivities. Generation of two vicinal stereocenters on the C═C double bonds was also achieved
Intramolecular Pd(II)-Catalyzed Aerobic Oxidative Amination of Alkenes: Synthesis of Six-Membered <i>N</i>-Heterocycles
作者:Zhan Lu、Shannon S. Stahl
DOI:10.1021/ol300030w
日期:2012.3.2
Use of a base-free Pd(DMSO)2(TFA)2 catalyst system enables the synthesis of six-membered nitrogen heterocycles via a Wacker-type aerobic oxidative cyclization of alkenes bearing tethered sulfonamides. Various heterocycles, including morpholines, piperidines, piperazines, and piperazinones, are accessible by this method.
The remarkable promotion of in situ formed Pt-cobalt oxide interfacial sites on the carbonyl reduction to allylic alcohols
作者:Chenyue Li、Changxuan Ke、Ruirui Han、Guoli Fan、Lan Yang、Feng Li
DOI:10.1016/j.mcat.2018.05.028
日期:2018.8
oxide-decorated Ptcatalyst at a Co/Ptatomic ratio of 0.6 was found to exhibit an exceptional catalytic performance with an extremely high 99% yield of cinnamyl alcohol under mild reaction conditions (2 MPa H2 and 80 °C). In contrast to that of the undecorated Pt one, the intrinsic activity of the cobalt oxide-decorated Pt-based one, i.e. the turnover frequency for cinnamaldehyde conversion (4.19 s−1)
由于Pt催化剂相对于C C键还原C O键具有相对令人满意的选择性,因此Pt催化剂在选择性地氢化α,β-不饱和醛以生产烯丙醇方面引起了越来越多的关注。在这里,通过一种简便的复合前体路线,制备了用于肉桂醛高选择性加氢的新型碳载氧化钴修饰的铂纳米催化剂。发现钴/铂原子比为0.6的人造氧化钴修饰Pt催化剂在适度的反应条件(2 MPa H 2和80°C)下显示出优异的催化性能,肉桂醇的收率极高(99%) 。与未装饰的Pt相比,氧化钴装饰的Pt基的固有活性即。肉桂醛转化的周转频率(4.19 s -1)显着增加了9.5倍。与先前报道的其他基于Pt的氢化催化剂相比,本发明的催化剂体系在催化性能方面表现出特别显着的提高。这种出色的催化效率可能与CoO x物种对Pt颗粒进行独特的几何和电子修饰相关,从而同时增加了暴露的活性金属表面和Pt 0物种的有利富电子态。相应地,可以提高肉桂醛的转化率,并可以增强羰基的吸附。CoO
Nickel‐Catalyzed Asymmetric Reductive 1,2‐Carboamination of Unactivated Alkenes
Starting from diverse alkene-tethered aryl iodides and O-benzoyl-hydroxylamines, the enantioselective reductive cross-electrophilic 1,2-carboamination of unactivatedalkenes was achieved using a chiral pyrox/nickel complex as the catalyst. This mild, modular, and practical protocol provides rapid access to a variety of β-chiral amines with an enantioenriched aryl-substituted quaternary carbon center