Regio- and Stereoselective Synthesis of 3-Pyrazolylidene-2-oxindole Compounds by Nucleophilic Vinylic Substitution of (E)-3-(Nitromethylene)indolin-2-one
[EN] A highly regio- and stereoselective synthesis of 3-alkylidene-2-oxindoles has been described through a nucleophilic vinylic substitution (SNV) of (E)-3-(nitromethylene)indolin-2-one using pyrazol-3-ones as nucleophiles and Et3N as a base. The reaction affords selectively the Z-isomer when pyrazol-3-ones without substituents at the 4 position are used. While the reaction is E-selective with 4- substituted pyrazolones. The stereoselectivity (up to >20:1) and the yields (up to 98%) are very high under mild reaction conditions. ; Financial support from the Agencia Estatal de Investigacion (AEI, Spanish Government) and Fondo Europeo de Desarrollo Regional (FEDER, European Union) (CTQ2017-84900-P) is acknowledged. C.V. thanks the Spanish Government for Ramon y Cajal contract (RYC-2016-20187). Access to NMR, MS and X-ray facilities from the Servei Central de Suport a la Investigacio Experimental (SCSIE)-UV is also acknowledged. ; Vila, C.; Slack, S.; Blay, G.; Muñoz Roca, MDC.; Pedro, JR. (2019). Regio- and Stereoselective Synthesis of 3-Pyrazolylidene-2-oxindole Compounds by Nucleophilic Vinylic Substitution of (E)-3-(Nitromethylene)indolin-2-one. Advanced Synthesis & Catalysis. 361(8):1902-1907. https://doi.org/10.1002/adsc.201900048 ; S ; 1902 ; 1907 ; 361 ; 8 ; Ring Nitrogen and Key Biomolecules: The Biochemistry of N-Heterocycles Ed.: E. G. Brown Springer 1998; ; Heterocyclic Chemistry Ed.: J. A. Joule K. Mills Wiley Chichester 2010; ; Modern Heterocyclic Chemistry Ed.: J. Alvarez-Builla J. J. Vaquero J. Barluenga Wiley-VCH Weinheim 2011. ; Marti, C., & Carreira, E. M. (2003). Construction of Spiro[pyrrolidine-3,3′-oxindoles] − Recent Applications to the Synthesis of Oxindole Alkaloids. European Journal of Organic Chemistry, 2003(12), 2209-2219. doi:10.1002/ejoc.200300050 ; Galliford, C. V., & Scheidt, K. A. (2007). Pyrrolidinyl-Spirooxindole Natural Products as Inspirations for the Development of Potential Therapeutic Agents. Angewandte Chemie International Edition, 46(46), 8748-8758. ...