A Polystyrene-Supported, Highly Recyclable Squaramide Organocatalyst for the Enantioselective Michael Addition of 1,3-Dicarbonyl Compounds to β-Nitrostyrenes
作者:Pinar Kasaplar、Paola Riente、Caroline Hartmann、Miquel A. Pericàs
DOI:10.1002/adsc.201200526
日期:2012.11.12
A chiral squaramide has been supported onto a polystyrene (PS) resin through a copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction and used as a very active, easily recoverable and highly reusable organocatalyst for the asymmetric Michaeladdition of 1,3-dicarbonylcompounds to β-nitrostyrenes. The PS-supported squaramide could be recycled up to 10 times.
Novel and highly efficient bifunctional calixarene thiourea derivatives as organocatalysts for enantioselective Michael reaction of nitroolefins with diketones
作者:Hayriye Nevin Genc、Abdulkadir Sirit
DOI:10.1007/s10847-017-0761-1
日期:2018.2
New bifunctional calixarene thiourea organocatalysts were synthesized and applied in catalytic asymmetric Michael addition of acetylacetone to various nitroolefins at room temperature. The corresponding adducts were obtained in good to excellent yields with excellent enantioselectivities (up to 92% ee). The present research demonstrates the advantages of incorporating two stereocontrolling structures
Highly enantioselectiveMichaelreactions between acetylacetone and trans-β-nitroolefins are achieved by a novel ferrocenophane-based tertiary amine-thiourea organocatalyst to provide the corresponding products in good to excellent yields (up to 95%) and enantioselectivities (up to 99% ee).
efficient method was developed to synthesize ferrocene-based bifunctionalamine–thioureasbearingmultiplehydrogen-bondingdonors. Asymmetric Michaeladdition of acetylacetone to nitroolefins catalyzed by these novel bifunctionalcatalysts affords the Michael adducts in high yield and moderate to excellent enantioselectivities. Multiplehydrogen-bonds play an important role in accelerating the reaction.