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Organocatalyzed Cascade Aza‐Michael/Michael Addition for the Asymmetric Construction of Highly Functionalized Spiropyrazolone Tetrahydroquinolines
Author(s) -
Li JunHua,
Du DaMing
Publication year - 2014
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201402706
Subject(s) - michael reaction , squaramide , stereocenter , enantioselective synthesis , bifunctional , cascade reaction , diastereomer , chemistry , organocatalysis , enantiomer , organic chemistry , combinatorial chemistry , stereochemistry , catalysis
Abstract An organocatalyzed diastereo‐ and enantioselective cascade aza‐Michael/Michael addition of 2‐tosylaminoenones to unsaturated pyrazolones has been developed to afford novel chiral spiropyrazolone tetrahydroquinolines containing three contiguous stereocenters. This cascade reaction proceeded well with 2 mol % chiral bifunctional tertiary amine squaramide catalyst to give the desired products in excellent yields (up to 99 %) with excellent diastereoselectivity (up to >25:1 diastereomeric ratio) and high enantioselectivity (up to 91 % enantiomeric excess).