Mukaiyama-Michael Reactions with<i>trans</i>-2,5-Diarylpyrrolidine Catalysts: Enantioselectivity Arises from Attractive Noncovalent Interactions, Not from Steric Hindrance
作者:Eeva K. Kemppainen、Gokarneswar Sahoo、Antti Piisola、Andrea Hamza、Bianka Kótai、Imre Pápai、Petri M. Pihko
DOI:10.1002/chem.201304240
日期:2014.5.12
the predicted and observed stereoselectivities. The analysis of intermolecular forces reveals that the enantioselectivity is mostly due to stabilizing noncovalentinteractions between the reacting partners, not due to sterichindrance. The role of attractivenoncovalentinteractions in enantioselective catalysis may be underappreciated.
Construction of Enantioenriched γ,γ-Disubstituted Butenolides Enabled by Chiral Amine and Lewis Acid Cascade Cocatalysis
作者:Chenguang Yu、Peng Ji、Yueteng Zhang、Xiang Meng、Wei Wang
DOI:10.1021/acs.orglett.1c02916
日期:2021.10.1
facile construction of chiral γ,γ-disubstituted butenolides. The synthetic manifold employs simple alkynoic acids instead of the preformed silyloxy furans or 5-substituted furan-2(3H)-ones. In situ formed 5-substituted furan-2(3H)-ones by AgNO3 or Ph3PAuCl/AgOTf catalyzedcyclization of alkynoic acids can smoothly engage in the subsequent chiral diphenylprolinol TMS-ether catalyzed Michael and Michael-aldol
在此,我们报告了一种用于轻松构建手性 γ,γ-二取代丁烯内酯的级联共催化策略。合成歧管使用简单的炔酸代替预先形成的甲硅烷氧基呋喃或 5-取代呋喃-2(3 H )-酮。通过AgNO 3或Ph 3 PAuCl/AgOTf 催化的炔酸环化原位形成的5-取代呋喃-2(3 H )-酮可以顺利地参与随后的手性二苯基脯氨醇TMS-醚催化的迈克尔和迈克尔-羟醛反应。级联过程是手性季 γ,γ-二取代丁烯内酯的通用方法。
Highly Enantioselective Direct Vinylogous Michael Addition of γ-Butenolide to Enals
An unprecedented and simple direct vinylogous addition of deconjugated butenolide to enals has been developed in excellent stereoselectivities (> 95% ee), with Aminal-PYrrolidine (APY) catalyst. This methodology allows for the efficient preparation of complex gamma-butenolide from readily available renewable resources. Furthermore, preliminary mechanistic investigations have allowed for the better understanding of the origin of both stereoselectivities and of the observed high reactivities.