title: Bifunctional cinchona alkaloid-squaramide-catalyzed highly enantioselective aza-Michael addition of indolines to α,β-unsaturated ketones.
abstract: An enantioselective aza-Michael addition of indolines to α,β-unsaturated ketones was achieved using a bifunctional cinchona alkaloid-derived chiral squaramide derivative. Various β-indolinyl ketone derivatives were obtained in good to excellent yields and with high enantioselectivity. DDQ or MnO2oxidation of indoline derivatives provided convenient access to various enantioenriched N-substituted indole derivatives.
authors.affiliation: Department of Chemistry and Medicinal Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, United States.
authors.forename: Arun K
authors.initials: AK
authors.lastname: Ghosh
authors.forename: Bing
authors.initials: B
authors.lastname: Zhou
keywords: Aza-Michael reaction; Cinchona alkaloid; Enantioselective; Indoline; Organocatalysis; β-Keto indoline