Enantioselective synthesis of (S,S)-ethambutol using proline-catalyzed asymmetric α-aminooxylation and α-amination
摘要:
An efficient enantioselective synthesis of (S,S)-ethambutol, a tuberculostatic antibiotic, has been achieved in 99% ee via both proline-catalyzed alpha-aminooxylation and alpha-amination of n-butyraldehyde as the key step. (c) 2006 Elsevier Ltd. All rights reserved.
The Direct Catalytic Asymmetricα-Aminooxylation Reaction: Development of Stereoselective Routes to 1,2-Diols and 1,2-Amino Alcohols and Density Functional Calculations
for the asymmetric alpha-oxidation reaction and found that several proline derivatives were also able to catalyze the transformation with excellent enantioselectivities. Moreover, stereoselective routes for the synthesis of monoprotected vicinal diols and hydroxyketones were found. In addition, short routes for the direct preparation of enantiomerically pure epoxides and 1,2-amino alcohols are presented
Dual-Organocatalyst-Promoted Asymmetric Cascade Reaction: Highly Efficient Construction of Enantiopure Fully Substituted Tetrahydro-1,2-oxazines
作者:Hua Lin、Xing-Wen Sun、Guo-Qiang Lin
DOI:10.1021/ol403463h
日期:2014.2.7
A four-component asymmetric α-aminoxylation/aza-Michael/Mannich cascade reaction for the construction of fully substituted chiral tetrahydro-1,2-oxazine derivatives was accomplished in high yields with excellent enantio- and diastereoselectivities under mild conditions. The 1,2-oxazine derivative could be transformed to the corresponding multifunctional chiral amino alcohol by N–O cleavage and fused-tricyclic
The direct proline-catalyzedasymmetric α-aminoxylation of aldehydes and ketones has been developed using nitrosobenzene as an oxygen source, affording α-anilinoxy-aldehydes and -ketones with excellent enantioselectivity. Reaction conditions have been optimized, and low temperature (−20 °C) was found to be a key for the successful α-aminoxylation of aldehydes, while slow addition of nitrosobenzene
Highly Enantioselective α-Aminoxylation of Aldehydes and Ketones in Ionic Liquids
作者:Kun Huang、Zhi-Zhen Huang、Xin-Liang Li
DOI:10.1021/jo061507g
日期:2006.10.1
As the first example for the synthesis of optically active α-hydroxyaldehydes and α-hydroxyketones in ionicliquids, we applied RTILs into l-proline catalyzed direct enantioselective α-aminoxylation of both aldehydes and ketones successfully. This protocol features a number of advantages, such as recycling of green solvents and chiral organocatalyst, high yields, excellent enantioselectivities, short
The direct catalytic enantioselective α-aminooxylation of aldehydes has been developed using nitrosobenzene as the oxygen source and l-proline as catalyst, affording versatile α-aminooxylated aldehydes in high yield with excellent enantioselectivities.