186352-80-7Relevant academic research and scientific papers
Diastereoselective and Enantiospecific Synthesis of 1,3-Diamines via 2-Azaallyl Anion Benzylic Ring-Opening of Aziridines
Li, Kangnan,Weber, Alexandria E.,Tseng, Luke,Malcolmson, Steven J.
supporting information, p. 4239 - 4242 (2017/08/23)
The 1,3-diamine motif appears in numerous complex molecules, yet there are few methods for the stereoselective construction of this moiety. Herein, we demonstrate a stereocontrolled synthesis of 1,3-diamines, which bear up to three contiguous stereogenic centers, through benzylic ring-opening of aziridines with 2-azaallyl anion nucleophiles. Reactions proceed efficiently (yield up to 95%), diastereoselectively (dr up to >20:1), site selectively, and enantiospecifically to deliver products with differentiated amino groups.
Rhodium complex with unsymmetrical vicinal diamine ligand: excellent catalyst for asymmetric transfer hydrogenation of ketones
Deshpande, Sudhindra H.,Shende, Vaishali S.,Shingote, Savita K.,Chakravarty, Debamitra,Puranik, Vedavati G.,Chaudhari, Raghunath V.,Kelkar, Ashutosh A.
, p. 51722 - 51729 (2015/06/25)
New unsymmetrical vicinal diamine ligands with systematic variation in the regio and stereo positions in the amine and sulphonamide groups were synthesized from cheap starting material such as norephedrine. Catalytic Asymmetric Transfer Hydrogenation (ATH) of aromatic alkyl ketones has been investigated using transition metal complexes and new derivatives of monotosylated unsymmetrical vicinal diamine ligands using sodium formate as the hydrogen source, in water and methanol. Chiral secondary alcohols were obtained with excellent enantioselectivity (>95% ee) and conversion of ketones (>95%) with [Rh(Cp)Cl2]2 and ligand 4 as a catalyst. Enantioselectivity was found to be slightly higher with the use of methanol as a solvent for ATH of ketones with sodium formate as the hydrogen source compared to water as a solvent and was found to be consistent with all the ketones investigated. The reaction mixture is homogeneous in methanol unlike in water, where substrate and product are insoluble in water and form separate phase, sodium formate being soluble in water. The activity and enantioselectivity obtained for ATH of ketones using [Rh(Cp)Cl2]2 and unsymmetrical vicinal diamine ligand as catalyst was comparable with the C2 symmetric benchmark ligands like TsDPEN ((1R,2R)-N-(p-tolylsulfonyl)-1,2-diphenylethylene-diamine), and TsCYDN ((1R,2R)-N-(p-tolylsulfonyl)-1,2-cyclohexyl,diamine) under similar reaction conditions. To the best of our knowledge, this is first example of the ATH of ketones with good activity and high enantioselectivity with [Rh(Cp)Cl2]2 and unsymmetrical vicinal diamine ligands as catalyst systems.
A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: Catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations
Bagchi, Vivek,Paraskevopoulou, Patrina,Das, Purak,Chi, Lingyu,Wang, Qiuwen,Choudhury, Amitava,Mathieson, Jennifer S.,Cronin, Leroy,Pardue, Daniel B.,Cundari, Thomas R.,Mitrikas, George,Sanakis, Yiannis,Stavropoulos, Pericles
supporting information, p. 11362 - 11381 (2014/09/17)
A CuI catalyst (1), supported by a framework of strongly basic guanidinato moieties, mediates nitrene-transfer from PhI=NR sources to a wide variety of aliphatic hydrocarbons (C-H amination or amidination in the presence of nitriles) and olefins (aziridination). Product profiles are consistent with a stepwise rather than concerted C-N bond formation. Mechanistic investigations with the aid of Hammett plots, kinetic isotope effects, labeled stereochemical probes, and radical traps and clocks allow us to conclude that carboradical intermediates play a major role and are generated by hydrogen-atom abstraction from substrate C-H bonds or initial nitrene-addition to one of the olefinic carbons. Subsequent processes include solvent-caged radical recombination to afford the major amination and aziridination products but also one-electron oxidation of diffusively free carboradicals to generate amidination products due to carbocation participation. Analyses of metal- and ligand-centered events by variable temperature electrospray mass spectrometry, cyclic voltammetry, and electron paramagnetic resonance spectroscopy, coupled with computational studies, indicate that an active, but still elusive, copper-nitrene (S = 1) intermediate initially abstracts a hydrogen atom from, or adds nitrene to, C-H and C=C bonds, respectively, followed by a spin flip and radical rebound to afford intra- and intermolecular C-N containing products.
Studies on the reaction of aziridines with nitriles and carbonyls: Synthesis of imidazolines and oxazolidines
Gandhi, Shikha,Bisai, Alakesh,Prasad, B. A. Bhanu,Singh, Vinod K.
, p. 2133 - 2142 (2007/10/03)
Reaction of N-tosylaziridines with nitriles and carbonyls to produce imidazolines and oxazolidines has been studied in the presence of a variety of Lewis acids. The reaction is efficient with 1 equiv of BF3· Et2O or Et3OBF4 in CH2Cl 2. However, it is catalytic with metal triflates that give the best results for cycloaddition of N-tosylaziridine with nitriles under solvent free conditions. The same reaction with carbonyls proceeds best in CH 2Cl2 in the presence of molecular sieves. Among various triflates, Zn(OTf)2 has been found to be the best. The cleavage of the N-Ts bond of the cyclized products has been studied in order to make it more versatile in synthesis. The mechanistic aspect of the reaction has been studied by using chiral aziridines as substrates. These formal [3 + 2] cycloaddition reactions of aziridines with nitriles and carbonyls proceed in a Ritter fashion.
Enantioselective nitrogen transfer to sulfides from nitridomanganese(V) complexes
Tomooka, Craig S.,Carreira, Erick M.
, p. 3773 - 3784 (2007/10/03)
We describe the facile preparation of novel, optically active nitridomanganese (V) complexes which serve as reagents for the electrophilic amination of sulfides. This amination method has several appealing features, including: i) the facile preparation of large quantities of the starting nitridomanganese reagent 3, ii) the preparation of acylsulfilimines 2 in optically active form, and iii) the mild reaction conditions employed.
Readily available nitrene precursors increase the scope of Evans' asymmetric aziridination of olefins
Soedergren, Mikael J.,Alonso, Diego A.,Andersson, Pher G.
, p. 3563 - 3565 (2007/10/03)
The performance of the copper-catalyzed asymmetric aziridination of olefins is highly dependent on the properties of the nitrene precursor. Our preliminary results show significant improvements of both enantioselectivity and chemical yields when [N-(4-nitrobenzenesulfonyl)imino]phenyliodinane 1b (p-NO2C6H4SO2N=IPh) is employed instead of the commonly used p-tolyl analog 1a (PhI=NTs). This paper reports the comparison of some nitrene precursors for the copper-catalyzed asymmetric aziridination of olefins, utilizing the olefin as the limiting component and 1.5 equivalents of the nitrene precursor. The aziridine derivatives of several olefins were obtained in moderate to excellent yields and with enantioselectivity up to 95% ee.
