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Organocatalytic Asymmetric Cascade Reactions of 7‐Vinylindoles: Diastereo‐ and Enantioselective Synthesis of C7‐Functionalized Indoles
Author(s) -
Shi Feng,
Zhang HongHao,
Sun XiaoXue,
Liang Jing,
Fan Tao,
Tu ShuJiang
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201405245
Subject(s) - enantioselective synthesis , indole test , chemistry , cascade , catalysis , isatin , cascade reaction , organocatalysis , combinatorial chemistry , phosphoric acid , stereochemistry , organic chemistry , chromatography
The first catalytic asymmetric cascade reaction of 7‐vinylindoles has been established by the rational design of such substrates. Cascade reactions with isatin‐derived 3‐indolylmethanols in the presence of a chiral phosphoric acid derivative allow the diastereo‐ and enantioselective synthesis of C7‐functionalized indoles as well as the construction of cyclopenta[ b ]indole and spirooxindole frameworks (all >95:5 d.r., 94–>99 % ee ). This approach not only addresses the great challenge of the catalytic asymmetric synthesis of C7‐functionalized indoles, but also provides an efficient method for constructing biologically important cyclopenta[ b ]indole and spirooxindole scaffolds with excellent optical purity. Investigation of the reaction pathway and activation mode has suggested that this cascade reaction proceeds through a vinylogous Michael addition/Friedel–Crafts process, in which dual H‐bonding activation of the two reactants plays a crucial role.