Practical Preparation of N-(1-Alkynyl)sulfonamides and Their Remote Diastereoselective Addition to Aldehydes via Titanation
摘要:
Aliphatic and aromatic suffonamides were alkynylated with 1-bromo-1-alkynes in the catalytic presence of Cul to give N-(1-alkynyl)sulfonamides in good to excellent yields. The acetylene-titanium complexes generated from N-(1-alkynyl)benzosultams underwent diastereoselective addition to aldehydes.
Nitrene Transfer Catalyzed by a Non-Heme Iron Enzyme and Enhanced by Non-Native Small-Molecule Ligands
作者:Nathaniel W. Goldberg、Anders M. Knight、Ruijie K. Zhang、Frances H. Arnold
DOI:10.1021/jacs.9b11608
日期:2019.12.18
for the construction of chemical bonds. Here we show that Pseudomonas savastanoi ethylene-forming enzyme (PsEFE), a non-heme iron enzyme, can catalyze olefin aziridination and nitrene C-H insertion, and that these activities can be improved by directed evolution. The non-heme iron center allows for facile modification of the primary coordination sphere by addition of metal-coordinating molecules, enabling
Highly Enantioselective Pd-Catalyzed Asymmetric Hydrogenation of Activated Imines
作者:You-Qing Wang、Sheng-Mei Lu、Yong-Gui Zhou
DOI:10.1021/jo0700878
日期:2007.5.1
complexes are highly effective catalysts for asymmetrichydrogenation of activated imines in trifluoroethanol. The asymmetrichydrogenation of N-diphenylphosphinyl ketimines 3 with Pd(CF3CO2)/(S)-SegPhos indicated 87−99% ee, and N-tosylimines 5 could gave 88−97% ee with Pd(CF3CO2)/(S)-SynPhos as a catalyst. CyclicN-sulfonylimines 7 and 11 were hydrogenated to afford the useful chiral sultam derivatives in
Pd /双膦配合物是用于活化的亚胺在三氟乙醇中不对称氢化的高效催化剂。Pd(CF 3 CO 2)/(S)-SegPhos对N-二苯基亚膦酰基酮亚胺3的不对称氢化表明ee为87-99%,N- tosylimines 5与Pd(CF 3 CO 2)可以得到88-97%ee /(S)-SynPhos作为催化剂。环状N-磺酰亚胺7和11 进行氢化,以79-93%ee的比重得到有用的手性舒马坦衍生物,这是重要的有机合成中间体和农业和医药制剂的结构单元。
Asymmetric transfer hydrogenation reactions of <i>N</i>-sulfonylimines by using alcohols as hydrogen sources
作者:Fan Yang、Jingchao Chen、Guoli Shen、Xuexin Zhang、Baomin Fan
DOI:10.1039/c8cc01284a
日期:——
A palladium/zinc co-catalytic system was established and successfully utilized in the asymmetric transfer hydrogenation reactions of N-sulfonylimines with alcohols as hydrogensources. Simple alcohols such as methanol, ethanol and benzyl alcohols are all variable hydrogensources that can reduce various N-sulfonylimines to the corresponding chiral amines with high optical purities in presence of this
Nickel‐Catalyzed Asymmetric Hydrogenation of
<i>N</i>
‐Sulfonyl Imines
作者:Bowen Li、Jianzhong Chen、Zhenfeng Zhang、Ilya D. Gridnev、Wanbin Zhang
DOI:10.1002/anie.201902576
日期:2019.5.27
An efficient nickel‐catalyzedasymmetric hydrogenation of N‐tBu‐sulfonyl imines was developed with excellent yields and enantioselectivities using (R,R)‐QuinoxP* as a chiral ligand. The use of a much lower catalyst loading (0.0095 mol %, S/C=10500) represents the highest catalytic activity for the Ni‐catalyzedasymmetric hydrogenations reported so far. Mechanistic studies suggest that a coordination
一种有效的镍催化的不对称氢化ñ -吨卜-磺酰亚胺是使用具有优良的产率和对映选择性显影([R ,- [R)-作为手性配体的QuinoxP *。使用低得多的催化剂负载量(0.0095 mol%,S / C = 10500)代表了迄今为止报道的Ni催化不对称氢化的最高催化活性。机理研究表明,镍盐及其配合物之间存在配位平衡,过量的镍盐会促进活性镍配合物的形成,因此提高了氢化效率。还通过计算研究了催化循环,以确定对映选择性的来源。发现在过渡态的催化剂和底物之间存在大量的弱吸引作用的广泛网络,这也可能有助于高催化活性。