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
A Novel Bifunctional Sulfonamide Primary Amine-Catalyzed Enantioselective Conjugate Addition of Ketones to Nitroolefins
作者:Fei Xue、Shilei Zhang、Wenhu Duan、Wei Wang
DOI:10.1002/adsc.200800445
日期:2008.10.6
The enantioselectiveconjugateaddition of a variety of ketones to nitroolefins has been developed. The process is efficiently catalyzed by a novelbifunctionalsulfonamideprimary amine in good yields and with good levels of enantioselectivity.
Highly enantioselective Michael addition of acetone to nitroolefins catalyzed by chiral bifunctional primary amine-thiourea catalysts with acetic acid
作者:Qing Gu、Xing-Tao Guo、Xin-Yan Wu
DOI:10.1016/j.tet.2009.04.087
日期:2009.7
Highlyenantioselective Michael reaction of acetone with a variety of nitroolefins catalyzed by N-[(1R,2R)-2-aminocyclohexyl]-N′-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-thiourea (1b) together with acetic acid is described. The Michael addition products were obtained in high yields (76–94%) and up to 96% ee.
N -[(1 R,2 R)-2-氨基环己基] -N '-(2,3,4,6-四-O-乙酰基-β- d催化的丙酮与多种硝基烯烃的高度对映选择性迈克尔反应描述了-吡喃葡萄糖基)-硫脲(1b)与乙酸。迈克尔加成产物的收率很高(76-94%),ee最高可达96%。
A Recyclable Organocatalyst for Asymmetric Michael Addition of Acetone to Nitroolefins
Based on different chiral diamine skeletons, a series of bifunctional primary amine-thiophosphoramides were synthesized and screened as the catalysts for the asymmetric Michael addition of acetone to both aromatic and aliphatic nitroolefins. Under the catalysis of a thiophosphoramide derived from 1,2-diphenylethane-1,2-diamine, the corresponding adducts were obtained in high yields (up to >99%) with
A series of bifunctional primary amine-thiophosphoramides were synthesized, which proven to be effective organocatalysts for the asymmetric Michael reaction of acetone to both aryl and alkyl nitro olefins in the presence of phenol as a protic additive. The corresponding adducts were obtained in excellent chemical yields (up to >99 %) with excellent enantioselectivities (up to 97 % ee).