Synthesis, Table of Contents Synthesis 2020; 52(07): 1047-1059DOI: 10.1055/s-0039-1690751 paper © Georg Thieme Verlag Stuttgart · New York Enantioselective N-Alkylation of Nitroindoles under Phase-Transfer Catalysis Dmitri Trubitsõn a Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia Email: tonis.kanger@taltech.ee , Jevgenija Martõnova a Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia Email: tonis.kanger@taltech.ee , Kristin Erkman a Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia Email: tonis.kanger@taltech.ee , Andrus Metsala a Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia Email: tonis.kanger@taltech.ee , Jaan Saame b Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia , Kristjan Kõster b Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia , Ivar Järving a Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia Email: tonis.kanger@taltech.ee , Ivo Leito b Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia , Tõnis Kanger ∗ a Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia Email: tonis.kanger@taltech.ee › Author Affiliations Recommend Article Abstract Buy Article All articles of this category Abstract An asymmetric phase-transfer-catalyzed N-alkylation of substituted indoles with various Michael acceptors was studied. Acidities of nitroindoles were determined in acetonitrile by UV-Vis spectrophotometric titration. There was essentially no correlation between acidity and reactivity in the aza-Michael reaction. The position of the nitro group on the indole ring was essential to control the stereoselectivity of the reaction. Michael adducts were obtained in high yields and moderate enantioselectivities in the reaction between 4-nitroindole and various Michael acceptors in the presence of cinchona alkaloid based phase-transfer catalysts. In addition to outlining the scope and limitations of the method, the geometries of the transition states of the reaction were calculated. Key words Key wordsasymmetric catalysis - heterocycles - Michael addition - organocatalysis - phase-transfer catalysis Full Text References References 1 For a recent review, see: Ciulla MG, Kumar K. Tetrahedron Lett. 2018; 59: 3223 2 Taylor RD, MacCoss M, Lawson AD. G. J. Med. 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