Catalytic Hydroetherification of Unactivated Alkenes Enabled by Proton‐Coupled Electron Transfer
作者:Elaine Tsui、Anthony J. Metrano、Yuto Tsuchiya、Robert R. Knowles
DOI:10.1002/anie.202003959
日期:2020.7.13
We report a catalytic, light‐driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible‐light irradiation in the presence of an IrIII‐based photoredox catalyst, a Brønsted base catalyst, and a hydrogen‐atom transfer (HAT) co‐catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct
我们报告了一种催化光驱动方法,用于未活化烯醇的分子内加氢醚化以提供环醚产品。这些反应在 Ir III基光氧化还原催化剂、布朗斯台德碱催化剂和氢原子转移 (HAT) 助催化剂存在下在可见光照射下发生。反应性烷氧基被认为是关键中间体,是通过质子耦合电子转移机制直接均裂激活醇 O−H 键而产生的。该方法表现出广泛的底物范围和高官能团耐受性,并且适应多种烯烃取代模式。还提出了证明该催化系统扩展到碳醚化反应的结果。
Isomerization of Olefins Triggered by Rhodium-Catalyzed CH Bond Activation: Control of Endocyclic β-Hydrogen Elimination
作者:Stephanie Y. Y. Yip、Christophe Aïssa
DOI:10.1002/anie.201500596
日期:2015.6.1
Five‐membered metallacycles are typically reluctant to undergo endocyclic β‐hydrogen elimination. The rhodium‐catalyzed isomerization of 4‐pentenals into 3‐pentenals occurs through this elementary step and cleavage of two CH bonds, as supported by deuterium‐labeling studies. The reaction proceeds without decarbonylation, leads to trans olefins exclusively, and tolerates other olefins normally prone
It is intended to provide a bicyclic γ-amino acid derivative having excellent activity as an α2δ ligand. The present invention provides a compound represented by the general formula (I):
wherein R1, R2, R2′, R4, R5, R6, R7, R8, and R8′ are a hydrogen atom or the like; and R3 is a hydrogen atom, a halogen atom, a C1-C6 alkyl group, or the like.
It is intended to provide a bicyclic γ-amino acid derivative having excellent activity as an α
2
δ ligand. The present invention provides a compound represented by the general formula (I):
wherein R
1
, R
2
, R
2′
, R
4
, R
5
, R
6
, R
7
, R
8
, and R
8′
are a hydrogen atom or the like; and R
3
is a hydrogen atom, a halogen atom, a C1-C6 alkyl group, or the like.
Enantioselective Intramolecular Hydroacylation of Alkynes by Rhodium Catalysis through Dynamic Kinetic Resolution
作者:Yoshihiro Oonishi、Kazuki Takagishi、Yi‐Min Liu、Yoshihiro Sato
DOI:10.1002/adsc.202300206
日期:2023.10.24
Rhodium-catalyzed enantioselective hydroacylation of racemic alkynals having a substituent at the α-position of the carbonyl group is described. This reaction can be applied for the wide range of substrates (22 examples), and mechanistic studies revealed that a dynamic kineticresolution (DKR) process occurs during the hydroacylation, giving various cyclic ketones in 47–93% yields with 59:41 to 97:3