A chiral primary-tertiary-1,2-diamine as an efficient catalyst in asymmetric aldehyde–ketone or ketone–ketone aldol reactions
摘要:
A novel chiral 1,2-diaminocyclohexane derivative, (1R,2R)-N-1-n-pentyl, N-1-benzyl-1,2-cyclohexanediamine, was designed, synthesized and applied as a catalyst in a number of aldol reactions between ketones and aryl aldehydes. Reactions between acetone and aryl aldehydes gave aldol products with moderate to good yields and with excellent enantioselectivity (up to yield 85%, ee 98%), while reactions between cyclohexanone and aryl aldehydes provided anti-beta-hydroxyketone products with excellent yields, diastereoselectivity and with enantioselectivity (up to 82% yield, anti/syn ratio 99:1, ee 99%). The aldol reactions between acetone and isatins were investigated, which afforded excellent yields and enantioselectivity (up to 95% yield, 98% ee). The (R)- and (S)-isomers of convolutamydine A were obtained with 95% yield and 96% ee, and 95% yield and 94% ee, respectively. (C) 2013 Elsevier Ltd. All rights reserved.
Application of Ruthenium Complexes of Triazole-Containing Tridentate Ligands to Asymmetric Transfer Hydrogenation of Ketones
作者:Tarn C. Johnson、William G. Totty、Martin Wills
DOI:10.1021/ol302354z
日期:2012.10.19
The synthesis of a series of tridentate ligands based on a homochiral 1,2-diamine structure attached to a triazole group and their subsequent applications to the asymmetric transferhydrogenation of ketones are described. In the best cases, alcohols of up to 93% ee were obtained. Although base is not required, the use of Ru3(CO)12 as metal source is essential, indicating a unique mechanism for the
Highly stereoselective direct aldol reactions catalyzed by a bifunctional chiral diamine
作者:Lei Li、Shaohua Gou、Fei Liu
DOI:10.1016/j.tetasy.2013.11.017
日期:2014.1
The enantioselective organocatalytic direct aldol reactions of ketones with various aldehydes were developed by using chiral 1,2-cyclohexanediamine COACH) based multifunctional ligands via a noncovalent catalysis mechanism. By using a catalyst, we also obtained functionalized 3-alkyl-3-hydroxyindolin-2-ones in high yields and with good to excellent enantioselectivities. (C) 2013 Elsevier Ltd. All rights reserved.