A novel and recyclable catalyst, a C3-symmetrical cinchonine-squaramide, has been developed for the asymmetric Michaeladdition of 1,3-dicarbonylcompounds to nitroalkenes. When using only 1 mol% of catalyst 1a for the reaction, high reaction yields with excellent enantioselectivities and diastereoselectivities (up to 96% yield,>99% ee,>99:1 dr) were achieved, in which the results for cyclic keto esters
Novelbifunctionalchiralsquaramide–amine organocatalysts have been developed by rational combination of pyrrolidine and a cinchona alkaloid. The catalysts promoted the enantioselective Michael addition of both mono- and diketones to a broad range of nitroalkenes providing the corresponding products in moderate to high yields with excellent enantioselectivities and diastereoselectivities (up to 96%
Novel Chiral Bifunctional L-Thiazoline-Thiourea Derivatives: Design and Application in EnantioselectiveMichael Reactions
作者:Qi Lai、Yang Li、Zhiyong Gong、Qingwen Liu、Chiyu Wei、Zhiguang Song
DOI:10.1002/chir.22540
日期:2015.12
Several novelchiralbifunctional L‐thiazoline‐thioureaderivatives were easily synthesized from commercially available L‐cysteine in high yield. These catalysts were subsequently applied to the enantioselective Michael addition of acetylacetone to β‐nitrostyrenes. The products with S configuration were obtained in 98% enantiomeric excess (ee) when the L‐thiazoline‐thioureaderivatives were used. A
Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives
作者:Zheng-Yi Li、Hong-Xiao Tong、Yuan Chen、Hong-Kui Su、Tangxin Xiao、Xiao-Qiang Sun、Leyong Wang
DOI:10.3762/bjoc.14.164
日期:——
rim-functionalized calix[4]thiourea cyclohexanediamine derivatives have been designed, synthesized and used as catalysts for enantioselective Michael addition reactions between nitroolefins and acetylacetone. The optimal catalyst 2 with a mono-thiourea group exhibited good performance in the presence of water/toluene (v/v = 1:2). Under the optimal reaction conditions, high yields of up to 99% and moderate
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