14996-79-3Relevant academic research and scientific papers
Oxidation of Nonactivated Anilines to Generate N-Aryl Nitrenoids
Deng, Tianning,Mazumdar, Wrickban,Ford, Russell L.,Jana, Navendu,Izar, Ragda,Wink, Donald J.,Driver, Tom G.
supporting information, p. 4456 - 4463 (2020/03/05)
A low-temperature, protecting-group-free oxidation of 2-substituted anilines has been developed to generate an electrophilic N-aryl nitrenoid intermediate that can engage in C-NAr bond formation to construct functionalized N-heterocycles. The exposure of 2-substituted anilines to PIFA and trifluoroacetic acid or 10 mol percent Sc(OTf)3 triggers nitrenoid formation, followed by productive and selective C-NAr and C-C bond formation to yield spirocyclic- or bicyclic 3H-indoles or benzazepinones. Our experiments demonstrate the breadth of these oxidative processes, uncover underlying fundamental elements that control selectivity, and demonstrate how the distinct reactivity patterns embedded in N-aryl nitrenoid reactive intermediates can enable access to functionalized 3H-indoles or benzazepinones.
I(III)-catalyzed oxidative cyclization - Migration tandem reactions of unactivated anilines
Deng, Tianning,Shi, Emily,Thomas, Elana,Driver, Tom G.
supporting information, p. 9102 - 9106 (2020/11/13)
An I(III)-catalyzed oxidative cyclization-migration tandem reaction using Selectfluor as the oxidant was developed that converts unactivated anilines into 3H-indoles is reported herein. The reaction requires as little as 1 mol % of the iodocatalyst and is mild, tolerating pyridine and thiophene functional groups, and the dependence of the diastereoselectivity of the process on the identity of the iodoarene or iodoalkane precatalyst suggests that the catalyst is present for the stereochemical determining C-N bond forming step.
Continuous Flow Synthesis and Purification of Aryldiazomethanes through Hydrazone Fragmentation
Lévesque, éric,Laporte, Simon T.,Charette, André B.
, p. 837 - 841 (2017/01/14)
Electron-rich diazo compounds, such as aryldiazomethanes, are powerful reagents for the synthesis of complex structures, but the risks associated with their toxicity and instability often limit their use. Flow chemistry techniques make these issues avoidable, as the hazardous intermediate can be used as it is produced, avoiding accumulation and handling. Unfortunately, the produced stream is often contaminated with other reagents and by-products, making it incompatible with many applications, especially in catalysis. Herein is reported a metal-free continuous flow method for the production of aryldiazomethane solutions in a non-coordinating solvent from easily prepared, bench-stable sulfonylhydrazones. All by-products are removed by an in-line aqueous wash, leaving a clean, base-free diazo stream. Three successful sensitive metal-catalyzed transformations demonstrated the value of the method.
Highly efficient and enantioselective α-arylation of cycloalkanones by scandium-catalyzed diazoalkane-carbonyl homologation
Rendina, Victor L.,Kaplan, Hilan Z.,Kingsbury, Jason S.
experimental part, p. 686 - 693 (2012/04/04)
Functionalized α-tertiary and -quaternary 2-arylcycloalkanones are rapidly accessed by scandium(III) triflate-catalyzed diazo-alkane-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 aryldiazo-methanes into unsubstituted cycloalkanones provides a single-step solution to the ongoing challenge of α-arylation. Georg Thieme Verlag Stuttgart · New York.
An enantioselective synthesis of 2-aryl cycloalkanones by sc-catalyzed carbon insertion
Rendina, Victor L.,Moebius, David C.,Kingsbury, Jason S.
, p. 2004 - 2007 (2011/07/07)
Current methods for asymmetric α-arylation require blocking groups to prevent reaction at the R0-carbon, basic conditions that promote racemization, or multistep synthesis. This work records the first catalytic enantioselective examples of the diazoalkane-carbonyl homologation reaction. Medium ring 2-aryl ketones are prepared in one step in up to 98:2 er and 99% yield from the unsubstituted lower homologue by Sc-catalyzed aryldiazomethyl insertion with simple bis- and tris(oxazoline) ligands.
Et2Zn-mediated rearrangement of bromohydrins
Li, Lezhen,Cai, Peijie,Guo, Qingxiang,Xue, Song
, p. 3516 - 3522 (2008/09/20)
(Chemical Equation Presented) A simple and highly efficient method for the rearrangement of bromohydrins mediated by Et2Zn to synthesize carbonyl compounds was described. Various β-bromo alcohols were treated with 0.6 equiv of Et2Zn to form a zinc complex in CH 2Cl2 at room temperature for 2 h, followed by 1,2-migration to give the corresponding carbonyl compounds. This remarkable and clean rearrangement is general for acyclic and cyclic bromohydrins, and a variety of ring-expansive and -contractive carbonyl compounds were obtained in good to excellent yields according to the feature of the starting bromohydrins. The functional group tolerance of organozinc reagents in this reaction will be useful in organic synthesis. The scope and limitations of this rearrangement process were also investigated.
Oxidative rearrangements of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol: A general, regiospecific synthesis of α-aryl ketones
Justik, Michael W.,Koser, Gerald F.
, p. 6159 - 6163 (2007/10/03)
The treatment of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol affords the corresponding α-aryl ketones. This oxidative rearrangement is general for acyclic and cyclic arylalkenes and permits regioselective syntheses of isomeric α-phenyl ketone pairs.
Direct α-arylation of ketones: The reaction of cyclic ketone enolates with diphenyliodonium triflate
Ryan, John H.,Stang, Peter J.
, p. 5061 - 5064 (2007/10/03)
Diphenyliodonium triflate 1a reacts with the lithium enolates of cyclic ketones 2 (ring size = 5 - 8), in the presence of stoichiometric quantities of copper cyanide, to afford the corresponding α-phenylated ketones 3 or α,α'-diphenylated ketones 4.
Ring Contraction of 2-Chlorocyclohexanone with Grignard Reagents
Hori, Mikio,Kataoka, Tadashi,Shimizu, Hiroshi,Imai, Eiji,Iwamura, Tatsunori,Maeda, Kaori
, p. 3599 - 3605 (2007/10/02)
The reaction of 2-chlorocyclohexanone with phenylmagnesium bromide in refluxing tetrahydrofuran unexpectedly afforded the ring-contracted product, cyclopentyl phenyl ketone, as the main product in moderate yield.The reactivities of several cyclic 2-haloketones were examined.Keywords - 2-chlorocyclohexanone; Grignard reaction; ring contraction; cyclopentyl phenyl ketone; solvent effect; THF; conformational isomer
