Asymmetric Michael Addition of Malonates to Enones Catalyzed by a Primary β-Amino Acid and Its Lithium Salt
作者:Masanori Yoshida、Mao Narita、Shoji Hara
DOI:10.1021/jo201429w
日期:2011.10.21
Highly enantioselective Michaeladdition of malonates to enones was achieved using a mixed catalyst consisting of a primary β-amino acid, O-TBDPS (S)-β-homoserine, and its lithium salt. Various cyclic and acyclic enones were converted into 1,5-ketoesters in high yields (up to 92%) with high enantioselectivity (up to 97% ee) under mild reaction conditions. Details of synthesis of the catalyst, optimization
Asymmetric organocatalytic conjugate addition of malonates to enones using a proline tetrazole catalyst
作者:Kristian Rahbek Knudsen、Claire E. T. Mitchell、Steven V. Ley
DOI:10.1039/b514636d
日期:——
5-Pyrrolidin-2-yltetrazole performs as a useful organocatalyst for the asymmetric addition of malonates to a range of enones, with good to excellent enantioselectivities.
Enantioselective Organocatalytic Michael Addition of Malonates to α,β-Unsaturated Ketones
作者:Pengfei Li、Shigang Wen、Feng Yu、Qiaoxia Liu、Wenjun Li、Yongcan Wang、Xinmiao Liang、Jinxing Ye
DOI:10.1021/ol802892h
日期:2009.2.5
derived from 1,2-diaminocyclohexane and 9-amino (9-deoxy) cinchona alkaloid was developed into asymmetricMichaeladdition of malonates to enones. A series of cyclic and acyclic enones could react very well with different malonates in the presence of 4 with 0.5−10 mol % catalyst loading affording chiral Michael adducts with excellent yields and ee values.
The enantioselective Michaeladditionreaction of malonates to α,β-unsaturated ketones is efficiently promoted by a combined dual-catalyst system composed of chiral thiourea and 4-pyrrolidinopyridine (PPY) in toluene. The expected Michael adducts with cyclic and acyclic enones are obtained in excellent yields and with excellent enantioselectivities.
A New Microwave-Assisted Organocatalytic Solvent-Free Synthesis of Optically Enriched Michael Adducts
作者:Antonio Procopio、Antonio De Nino、Monica Nardi、Manuela Oliverio、Rossella Paonessa、Raffaele Pasceri
DOI:10.1055/s-0030-1258126
日期:2010.7
A high-yielding reaction protocol for the microwave-assisted organocatalytic conjugate addition of diethyl malonate to enones under solvent-free conditions is proposed. The method still permits the use of cheap and commercially available L -proline furnishing very good performance at least in the case of 1-alkyl-3-monosubstituted enones.