选择性双体O-酸盐阿尔多尔/迈克尔反应
Yuhei Yamamoto1, Norie Momiyama, Hisashi Yamamoto
1Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA.
Journal of the American Chemical Society
|May 13, 2004
概括
通过与氨基催化剂一起进行双重的酸醇/迈克尔反应,在酸迪尔斯-阿尔德添加物中实现了高的反选择性. 这种方法与传统的酸醇反应相比,产生了相反的区域化学结果.
科学领域:
- 有机化学 有机化学
- 不对称的合成方法
背景情况:
- 酸-迪尔斯-阿尔德反应是合成含异环的宝贵工具.
- 在这些反应中控制酶选择性和区域化学仍然是一个挑战.
研究的目的:
- 开发一种新的,高度抗选择性的方法来合成酸的Diels-Alder添加物.
- 为了研究新反应路径的区域化学结果.
主要方法:
- 一种由氨基催化的双酸醇/迈克尔反应.
- 进行X射线晶体分析以确定区域化学结果.
- 用银-BINAP催化剂对子反应进行研究,以逐步进行区域化学控制.
主要成果:
- 在酸的迪尔斯-阿尔德 adduct 构成中实现了均高的 enantioselectivity.
- 区域化学结果与标准酸醇反应的结果相反.
- 用银-BINAP催化剂证明了区域化学的逐步控制.
结论:
- 开发的并联反应提供了一条有效的途径,以获得聚丰富的酸Diels-Alder添加物.
- 反向的区域选择性提供了新的合成可能性.
- 催化剂的选择显著影响反应的区域化学结果.
更多相关视频
相关概念视频
01:08Base-Catalyzed Aldol Addition Reaction
As depicted in Figure 1, base-catalyzed aldol addition involves adding two carbonyl compounds in aqueous sodium hydroxide to form a β-hydroxy carbonyl compound.
01:08Conjugate Addition of Enolates: Michael Addition
The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition reactions of active methylene compounds, such as β-diketones, β-keto esters, β-keto nitriles, and α-nitro ketones, are called Michael addition reactions.
01:15Acid-Catalyzed Aldol Addition Reaction
The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The acid-catalyzed aldol reaction is depicted in Figure 1.
01:27Aldol Condensation with β-Diesters: Knoevenagel Condensation
The Knoevenagel condensation is an aldol-type reaction involving the condensation of aldehydes or ketones with active methylene compounds such as β-diesters to produce substituted olefins.
01:27Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).
01:19Nitrosation of Enols
The nitrosation reaction is one of the methods of preparing 1,2-diketones. The enol tautomer of the starting ketone reacts with sodium nitrite in hydrochloric acid, generating the 1,2-diketone after hydrolysis.