<i>N</i>-Primary-Amine-Terminal β-Turn Tetrapeptides as Organocatalysts for Highly Enantioselective Aldol Reaction
作者:Feng-Chun Wu、Chao-Shan Da、Zhi-Xue Du、Qi-Peng Guo、Wei-Ping Li、Lei Yi、Ya-Ning Jia、Xiao Ma
DOI:10.1021/jo9005766
日期:2009.7.3
solution. They were first applied to catalyze aldolreactions, and were found to be effective catalysts for the transformations. The tetrapeptide Val-d-Pro-Gly-Leu-OH (1g) was the optimal organocatalyst. It was shown that the intensive β-turn conformation, indicated by CD and NOESY spectra, contributed to the (R)-aldol and high enantioselectivity of the reaction of acetone in MeOH, whereas the sharply varied
设计并合成了四肽,该四肽包含一个终止的伯胺和构象受限的d -Pro-Gly或d -Pro-Aib(2-氨基异丁酸)链段作为强β-转核元素,并通过N-模块二肽与溶液中的C模块二肽。它们首先被用于催化羟醛反应,并被发现是有效的转化催化剂。四肽Val- d -Pro-Gly-Leu-OH(1g)是最佳的有机催化剂。结果表明,在密集的β转角构象,通过CD和NOESY光谱表明,促成了(ř)-丙酮中的丙酮反应具有较高的对映选择性,而急剧变化的构象应有助于1,2-二氯乙烷(DCE)中反应的低对映选择性和(S)产物。羟基丙酮反应中的不对称诱导不受溶剂的影响,在MeCN中添加1克添加剂(S)-BINOL可达到主要的反产物。
Highly enantioselective aldol reactions using a tropos dibenz[c,e]azepine organocatalyst
作者:Barry Lygo、Christopher Davison、Timothy Evans、James A.R. Gilks、John Leonard、Claude-Eric Roy
DOI:10.1016/j.tet.2011.09.101
日期:2011.12
The four-step synthesis of a chiral primary tertiary diamine salt, possessing a tropos dibenz[c,e]azepine ring is described. It is shown that 3.5–5 mol % of this salt is capable of promoting highly enantioselective crossed-aldol reactions between cyclohexanone and a series of aromatic aldehydes. In all cases, the aldol reactions proceed with high diastereoselectivity for the anti-aldol product. The
Highly Diastereo- and Enantioselective Aldol Reactions in Common Organic Solvents Using<i>N</i>-Arylprolinamides as Organocatalysts with Enhanced Acidity
作者:Jarugu Narasimha Moorthy、Satyajit Saha
DOI:10.1002/ejoc.200800960
日期:2008.12.29
steric crowding has been synthesized and its catalytic activity explored for enantioselectivealdolreactions. In DMF containing 10 mol-% of TFA, all arylamides are found to catalyze the reaction between cyclohexanone and a variety of electrophilic aldehydes leading to aldols in excess of 90 % yield and >95 % enantioselectivity. The perfluorophenyl catalyst 8 is found to perform best with a broad substrate
SULFONAMIDE-BASED ORGANOCATALYSTS AND METHOD FOR THEIR USE
申请人:Carter Rich Garrett
公开号:US20100184986A1
公开(公告)日:2010-07-22
Organocatalysts, particularly proline sulfonamide organocatalysts, having a first general formula as follows are disclosed.
Embodiments of a method for using these organocatalysts also are disclosed. The method comprises providing a disclosed organocatalyst, and performing a reaction, often an enantioselective or diastereoselective reaction, using the organocatalyst. Solely by way of example, disclosed catalysts can be used to perform aldol reactions, conjugate additions, Michael additions, Robinson annulations, Mannich reactions, α-aminooxylations, α-hydroxyaminations, α-aminations and alkylation reactions. Certain of such reactions are intramolecular cyclizations used to form cyclic compounds, such as 5- or 6-membered rings, having one or more chiral centers. Disclosed organocatalysts generally are much more soluble in typical solvents used for organic synthesis than are known compounds. Moreover, the reaction yield is generally quite good with disclosed compounds, as is their enantioselective and diastereoselective effectiveness.
Synthesis and Characterization of Monosaccharide Derivatives and Application of Sugar-Based Prolinamides in Asymmetric Synthesis
作者:Jyoti Agarwal、Rama Krishna Peddinti
DOI:10.1002/ejoc.201200522
日期:2012.11
were converted into the corresponding prolinamide organocatalysts (i.e., 1a, 2a, 3a, and 3b) in high yields. The catalytic activity of these sugar-based prolinamide organocatalysts was demonstrated in asymmetric aldol reactions in various solvents and at different temperatures. The oraganocatalyst 3a was shown to be an efficient and powerful organocatalyst for the enantioselective aldol reaction of various