Primary Amine-Thioureas with Improved Catalytic Properties for “Difficult” Michael Reactions: Efficient Organocatalytic Syntheses of (S)-Baclofen, (R)-Baclofen and (S)-Phenibut
作者:Michail Tsakos、Christoforos G. Kokotos、George Kokotos
DOI:10.1002/adsc.201100636
日期:2012.3
Among the class of primary amine‐thioureas based on tert‐butyl esters of α‐amino acids, the most efficient organocatalyst for “difficult” Michaelreactions was identified. The derivative based on (S)‐di‐tert‐butyl aspartate and (1R,2R)‐diphenylethylenediamine provided the products of the reaction between aryl methyl ketones and nitroolefins in excellent yields and enantioselectivities. In addition
Enantioselective Conjugate Addition of Both Aromatic Ketones and Acetone to Nitroolefins Catalyzed by Chiral Primary Amines Bearing Multiple Hydrogen-Bonding Donors
of chiral primary amine catalysts bearing multiple hydrogen-bonding donors have been designed and synthesized. The newly developed bifunctional organocatalysts efficiently catalyzed not only enantioselectiveconjugateaddition of aromatic ketones to nitroolefins in good yields (up to 87%) with excellent enantioselectivities (97→99% ee) but also enantioselectiveconjugateaddition of acetone to nitroolefins
Highly Enantioselective Michael Addition of Nitroalkanes to Chalcones Using Chiral Squaramides as Hydrogen Bonding Organocatalysts
作者:Wen Yang、Da-Ming Du
DOI:10.1021/ol102294g
日期:2010.12.3
squaramide-based organocatalysts were facilely synthesized and applied as hydrogen bonding organocatalysts in the enantioselectiveMichaeladdition of nitroalkanes to chalcones. These organocatalysts promoted the Michaeladdition with low catalyst loading under high temperature (80 °C), affording the desired R or S enantiomers of the products flexibly in high yields with excellent enantioselectivities (93−96%
A General, Scalable, Organocatalytic Nitro-Michael Addition to Enones: Enantioselective Access to All-Carbon Quaternary Stereocenters
作者:Xiaodong Gu、Yuanyuan Dai、Tingting Guo、Allegra Franchino、Darren J. Dixon、Jinxing Ye
DOI:10.1021/acs.orglett.5b00387
日期:2015.3.20
Michael addition of nitromethane to five-, six-, and seven-membered β-substituted cyclic enones with excellent enantioselectivity, offering scalable, asymmetric access to all-carbon quaternary stereocenters. The reaction scope can be expanded to include linear acyclic enones, and excellent levels of enantioselectivity are also observed. Furthermore, this organocatalytic, asymmetric nitro-Michael reaction
Asymmetric Michael Addition of Aromatic Ketones to Nitroolefins Catalyzed by Simple Chiral Bifunctional Primary Amine-Thioureas
作者:Liangliang Wang、Xiaoying Xu、Jun Huang、Lin Peng、Qingchun Huang、Lixin Wang
DOI:10.2174/157017810791514652
日期:2010.7.1
Simple chiral primary amine-thiourea catalysts derived from chiral 1,2-diphenylethylenediamine were found to catalyze direct Michael addition of aromatic ketones to nitroolefins with good enantioselectives (up to 86% ee) and excellent yields (up to 97%) for a broad range of substrates and successfully used in the preparation of (R)-Balcofen.