title: Organocatalyzed enantioselective synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylates.
abstract: The organocatalyzed enantioselective synthesis of biologically active 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylate derivatives was achieved using bifunctional cinchona alkaloids as the catalysts. Using quinine thiourea as the catalyst, the tandem Michael addition-cyclization reaction between 1,3-cyclohexanediones and alkylidenecyanoacetate derivatives gives the desired products in high yields (up to 92%) and good ee values (up to 82%).
authors.affiliation: Department of chemistry, University of Texas at San Antonio, One UTSA circle, San Antonio, TX, 78249-0698, USA.
authors.forename: Naresh
authors.initials: N
authors.lastname: Ramireddy
authors.forename: Santhi
authors.initials: S
authors.lastname: Abbaraju
authors.forename: Cong-Gui
authors.initials: CG
authors.lastname: Zhao
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