Catalytic Diastereo- and Enantioselective Vinylogous Mannich Reaction of Alkylidenepyrazolones to Isatin-Derived Ketimines

Abstract

[EN] A valuable organocatalytic vinylogous Mannich reaction between alkylidenepyrazolones and isatin-derived ketimines has been successfully established. Squaramide organocatalyst, prepared from quinine, catalyzed the diastereo- and enantioselective vinylogous Mannich addition, affording a range of aminooxindole-pyrazolone adducts (24 examples) with excellent outcomes: up to 98% yield with complete diastereoselectivity and excellent enantioselectivity (up to 99% ee). Additionally, different synthetic transformations were performed with the chiral pyrazolone-oxindole adducts.Financial support from the Agencia Estatal de Investigacion (AEI, Spanish Government) and Fondo Europeo de Desarrollo Regional (FEDER, European Union) (PID2020-116944GB) and from Conselleria d'Innovacio, Universitat, Ciencia i Societat Digital (AICO/2020/68) is acknowledged. L.C.-F. thanks the Universitat de Valencia for a predoctoral grant. C.V. thanks the Spanish Government for a RyC contract (RYC2016-20187). Access to the NMR, MS, and X-ray facilities from the Servei Central de Suport a la Investigacio Experimental (SCSIE)-UV is also acknowledged.Carceller-Ferrer, L.; Vila, C.; Blay, G.; Muñoz Roca, MDC.; Pedro, JR. (2021). Catalytic Diastereo- and Enantioselective Vinylogous Mannich Reaction of Alkylidenepyrazolones to Isatin-Derived Ketimines. Organic Letters. 23(19):7391-7395. https://doi.org/10.1021/acs.orglett.1c0257173917395231