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
Hydrogen bonding mediated enantioselective organocatalysis in brine: significant rate acceleration and enhanced stereoselectivity in enantioselective Michael addition reactions of 1,3-dicarbonyls to β-nitroolefins
作者:Han Yong Bae、Surajit Some、Joong Suk Oh、Yong Seop Lee、Choong Eui Song
DOI:10.1039/c1cc13637b
日期:——
Brine provides remarkable rateacceleration and a higher level of stereoselectivity over organic solvents, due to the hydrophobic hydration effect, in the enantioselectiveMichael addition reactions of 1,3-dicarbonyls to beta-nitroolefins using chiral H-donors as organocatalysts.
Our findings on the bifunctional squaramide‐catalyzed enantioselective conjugateaddition of β‐ketoamides to nitroolefins are disclosed. It appears that simple acyclic methylene β‐ketoamides, unlike the extensively studied β‐ketoesters, afford the products in excellent diastereoselectivities, and maintain high yields and enantioselectivities. Moreover, competition and kinetic studies were conducted
One pot domino reaction accessing γ-nitroesters: synthesis of GABA derivatives
作者:Fabricio F. Naciuk、Debora Z. Vargas、Caroline R. M. D'Oca、Celso C. Moro、Dennis Russowsky
DOI:10.1039/c4nj01552e
日期:——
γ-Nitroesters are synthesized by theone potdomino process. GABA derivatives phenibut and baclofen were readily accessed.
γ-硝基酯通过一锅法多米诺过程合成。GABA衍生物苯硫胺和巴克洛芬可以轻松获得。
Enantioselective Addition of Malonates and β-Keto Esters to Nitroalkenes over an Organonickel-Functionalized Periodic Mesoporous Organosilica
作者:Ronghua Jin、Ketang Liu、Daquan Xia、Qingqian Qian、Guohua Liu、Hexing Li
DOI:10.1002/adsc.201200222
日期:2012.11.26
well-defined single-site chiral bis(cyclohexyldiamine)-based nickel(II) active centers incorporated within the PMO material. In particular, as a heterogeneous chiral catalyst, this periodic mesoporous organosilica showed high catalytic activity and excellent enantioselectivity in asymmetricMichaeladdition of 1,3-dicarbonyl compounds to nitroalkenes (more than 92% conversions and up to 99% ee values). More