73843-10-4Relevant 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.
Chemoselective one-pot synthesis of β-keto sulfones from ketones
Rawat, Vikas S.,Reddy, Perla L. M.,Sreedhar, Bojja
, p. 5165 - 5168 (2014/01/23)
A practical method to synthesize substituted β-keto sulfones directly from ketones at room temperature has been developed. This method involves the nucleophilic addition of a base generated enolate to sulfonyl iodide. The reaction shows high chemoselectivity for the addition of a sulfonyl group to an α-carbon over a hydroxyl group. In addition, the given protocol provides good to excellent yields of β-keto sulfones under mild reaction conditions. Moreover, the regiochemical aspect of the protocol is also explored.
Metal-free desulfonylation reaction through visible-light photoredox catalysis
Yang, Deng-Tao,Meng, Qing-Yuan,Zhong, Jian-Ji,Xiang, Ming,Liu, Qiang,Wu, Li-Zhu
, p. 7528 - 7532 (2013/12/04)
The desulfonylation of β-arylketosulfones has been achieved in good to excellent yields by using 3-W blue LEDs light, 1 mol-% organic dye eosin Y bis(tetrabutylammonium salt) as photocatalyst, and diisopropylethylamine as reducing agent. Mechanistic studies demonstrate that oxidative quenching of the excited eosin Y by β-arylketosulfones plays a crucial role in the present photoredox catalytic cycle. Reductive desulfonylation is essential to enable to use of a sulfone as an auxiliary group. For reductive removal of sulfones, highly aggressive metal-containing reducing agents and harsh reaction conditions are often employed. In this paper, metal-free desulfonylation of β-arylketosulfones can be achieved efficiently at room temperature under visible-light irradiation.
Dual secondary amine/N-heterocyclic carbene catalysis in the asymmetric Michael/cross-benzoin cascade reaction of β-oxo sulfones with enals
Enders, Dieter,Grossmann, Andre,Huang, He,Raabe, Gerhard
supporting information; experimental part, p. 4298 - 4301 (2011/09/16)
Polyfuncionalized cyclopentanones with three contiguous stereogenic centers were formed in good to excellent yields and stereoselectivities by utilizing a secondary amine/N-heterocyclic carbene catalytic system in the reaction of β-oxo sulfones with unsaturated aldehydes. In addition, the influence of the catalysts on the diastereoselectivity of the final product was studied by 1H NMR spectroscopy. The combination secondary amine/N-heterocyclic carbene turned out to be a good dual catalytic system for the reaction of β-oxo sulfones with enals leading to polyfunctionalized cyclopentanones in good to excellent yields and stereoselectivities. Further improvement of the enantiomeric excess is possible by crystallization. Direct observations by NMR spectroscopy revealed that the carbene catalyst alone is triggering the diastereoselectivity.
Investigation of oxacycle formation by base-promoted endo-mode ring-closing reaction of allenes
Kitagaki, Shinji,Kawamura, Takamasa,Shibata, Daisuke,Mukai, Chisato
experimental part, p. 11086 - 11095 (2009/04/11)
The base-promoted endo-mode ring closure of electron-withdrawing group-substituted allenes provided the following interesting results: (1) the endo-mode ring-closing reaction of 1-(benzyloxycarbonyl)-1-(ω-hydroxyalkyl)allenes smoothly proceeded during the
The formation of bicyclo[n.2.0]alkan-1-ols from the reaction of the lithium enolates of simple ketones and phenyl vinyl sulfoxide
Loughlin, Wendy A.,McCleary, Michelle A.
, p. 1347 - 1353 (2007/10/03)
The enolates generated from cyclopentanone, cycloheptanone or cyclooctanone and LDA at -78°C in THF react with (±)-phenyl vinyl sulfoxide under controlled conditions of temperature, reaction time, and concentration. Upon oxidation with MCPBA of the produc
Efficient and stereoselective synthesis of bicyclo[3.2.1]octan-8-ones: Synthesis and palladium-catalyzed isomerization of functionalized 2-vinyl-2,3,3a,4,5,6-hexahydro-2,3-benzofurans
Langer, Peter,Holtz, Edith,Saleh, Nehad N. R.
, p. 917 - 928 (2007/10/03)
A new C,O-cyclodialkylation of dilithiated cyclic β-keto esters and β-keto sulfones with 1,4-dibromo-2-butene is reported which results in regio- and diastereoselective formation of 2-vinyl-2,3,3a,4,5,6-hexahydro-2,3-benzofurans. The products could be eff
Phenylsulfonyl as a β participating group
Lambert, Joseph B.,Beadle, Beth M.,Kuang, Kuiyang
, p. 9241 - 9246 (2007/10/03)
The phenylsulfonyl group (PhSQ2) has been examined for its β effect properties. The stereochemical relationship was varied between phenylsulfonyl and a nucleophilic leaving group (nucleofuge) separated by two carbons. Mechanisms were distinguished through solvent effects on rates and products. When the stereochemistry between the two groups was gauche, the only effect of phenylsulfonyl was strong inductive retardation in a mechanism involving solvent participation. With the antiperiplanar stereochemistry, however, the mechanism clearly changed to carbocation formation with a small kinetic acceleration. Thus, phenylsulfonyl is a weak β effect substituent. This remarkable property for a strongly electron-withdrawing group occurs most likely through hyperconjugation or possibly through anchimeric assistance.
Chemoselective oxidation of sulfides to sulfones with magnesium monoperoxyphthalate (MMPP) on silica gel support in methylene chloride solvent
Ali, Mohammed Hashmat,Bohnert, Gary J.
, p. 2983 - 2998 (2007/10/03)
A simple, efficient and chemoselective, non-aqueous procedure for oxidation of sulfides to the corresponding sulfones with magnesium monoperoxyphthalate on hydrated silica gel has been developed.
