Synthesis in mesoreactors: Ru(porphyrin)CO-catalyzed aziridination of olefins under continuous flow conditions
作者:S. Rossi、A. Puglisi、M. Benaglia、D. M. Carminati、D. Intrieri、E. Gallo
DOI:10.1039/c6cy00207b
日期:——
The Ru(porphyrin)CO-catalyzed addition of aryl azides to styrenes to afford N-aryl aziridines was successfully performed for the first time in mesoreactors under continuousflow conditions. Mesofluidic technology allowed for a rapid screening of different parameters and a quick identification of the optimized reaction conditions.
Highly Efficient and Enantioselective α-Arylation of Cycloalkanones by Scandium-Catalyzed Diazoalkane-Carbonyl Homologation
作者:Jason Kingsbury、Victor Rendina、Hilan Kaplan
DOI:10.1055/s-0031-1289650
日期:2012.3
Functionalized α-tertiary and -quaternary 2-arylcycloalkanones are rapidly accessed by scandium(III) triflate-catalyzed diazoalkane-carbonyl homologations. Recent developments have allowed for carbon insertion reactions to be performed with catalyst loadings as low as 0.5 mol% on scales up to 5 mmol. Pairing readily available bis- and tris(oxazoline) based ligands with scandium triflate allows access to arylated medium ring carbocycles with enantioselectivities up to 98:2 er and >98% yield. The formal C-C insertion of aryldiazomethanes into unsubstituted cycloalkanones provides a single-step solution to the ongoing challenge of α-arylation.
<i>In Situ</i> Generation of Zinc Carbenoids from Diazo Compounds and Zinc Salts: Asymmetric Synthesis of 1,2,3-Substituted Cyclopropanes
作者:Sébastien R. Goudreau、André B. Charette
DOI:10.1021/ja9074776
日期:2009.11.4
first enantioselective cyclopropanation of alkenes usingzinccarbenoids generated in situ from diazo compounds and zinc salts is reported. This new method allows the highly enantio- and diastereoselective synthesis of 1,2,3-substituted cyclopropanes via aryl-substituted carbenoids. The first Simmons-Smith reaction using a catalytic amount of zinc to generate enantioenriched cyclopropane is also reported
Synthesis, Structure, and Reactivity of η<sup>2</sup>-N<sub>2</sub>-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond
作者:Anne W. Kaplan、Jennifer L. Polse、Graham E. Ball、Richard A. Andersen、Robert G. Bergman
DOI:10.1021/ja981340b
日期:1998.11.1
A series of η2-N2-titanium aryldiazoalkane complexes Cp*2Ti(N2CHAr) (5−10), where Ar is a para-substituted aryl group, have been prepared by addition of aryldiazoalkanes to Cp*2Ti(C2H4) (4). Unlike most diazoalkanecomplexes, they release dinitrogen thermally to give transient carbenecomplexes which may be trapped with styrene to form the titanacyclobutane complexes Cp*2Ti(CHArCHPhCH2) (11−15). The
一系列 η2-N2-钛芳基重氮烷配合物 Cp*2Ti(N2CHAR) (5-10),其中 Ar 是对位取代的芳基,通过将芳基重氮烷加成到 Cp*2Ti(C2H4) (4) 上制备。与大多数重氮烷配合物不同,它们通过热释放二氮以产生瞬态卡宾配合物,这些配合物可能会被苯乙烯捕获以形成钛环丁烷配合物 Cp*2Ti(CHARCHPhCH2) (11-15)。这些反应在 78.0 °C 下甲苯-d8 中的动力学已通过 1 H NMR 光谱学进行了检查。Hammett 分析 (ρ = − 0.26) 表明该反应对重氮烷配体芳环上的对位取代基相对不敏感,但是基于 E 和 C 的双参数取代基常数分析的应用表明,这可能是由于几乎完全补偿了每个取代基对反应速率的共价和静电贡献。芳基重氮烷配合物在低于 75 °C 的温度下的稳定性允许在没有竞争性 N2 lo...
Bulky <i>N</i>-Phosphinomethyl-Functionalized N-Heterocyclic Carbene Chelate Ligands: Synthesis, Molecular Geometry, Electronic Structure, and Their Ruthenium Alkylidene Complexes
A new, extremely bulky, and electron-rich N-phosphinomethyl-functionalized N-heterocyclic carbene ligand, 5a (tBuNHCPtBu), and a somewhat less bulky congener, 5b (MesNHCPtBu), forming five-membered chelate rings with metal centers, have been synthesized in four steps starting from the easily accessible di-tert-butyl(hydroxymethyl)phosphine oxide (1). 5a was isolated and fully characterized by spectroscopic
一种新的,非常笨重且富含电子的N-膦甲基甲基官能化的N-杂环卡宾配体5a(t Bu NHCP t Bu)和体积较小的同类物5b(Mes NHCP t Bu),形成五元螯合物从容易获得的二叔丁基(羟甲基)氧化膦(1)开始,已通过四个步骤合成了具有金属中心的环。分离并通过包括紫外光电子能谱和X射线衍射的能谱方法充分表征了5a。的反应5a中,以[Ru(COD)氯2 ] n在氢气压力下或与[Ru(p- Cymene)Cl 2 ] 2导致形成不饱和双核络合物[Ru(t Bu NHCP t Bu)(μ-Cl)(Cl)] 2(6) ,它用作使用取代的苯基重氮甲烷(p -XC 6 H 4(CH)N 2; X = H(a),Br(b),CF 3(c)的一系列钌卡宾配合物(7a - f)的前体),NO 2,(d),CH 3(e))和三甲基甲硅烷基重氮甲烷(f)。用膦或吡啶配体处理6导致形成单核加合物[Ru(t