73843-10-4Relevant articles and documents
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.
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.
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.
