Chiral selenium π-acid catalysis has for a long time been lagging behind other areas of asymmetriccatalysis due to a lack of highly enantioselective catalysts. In this regard, we recently developed the firstchiral selenium π-acid catalyst which performs the oxidative cyclization of β,γ-unsaturated carboxylic acids with high enantioselectivities. We report herein our improved synthesis of this chiral
developed using a chiral monodentate oxazoline (MOXin) ligand. Various indoles react at C3 position with aminoquinoline-coupled 3-alkenamides to give γ addition products in good to excellent yield and enantioselectivity. This study represents an important advance of the development of chiral monodentate oxazoline ligands, which have been underexplored for asymmetriccatalysis.
A Chiral Electrophilic Selenium Catalyst for Highly Enantioselective Oxidative Cyclization
作者:Yu Kawamata、Takuya Hashimoto、Keiji Maruoka
DOI:10.1021/jacs.6b01462
日期:2016.4.27
Chiral electrophilic selenium catalysts have been applied to catalytic asymmetric transformations of alkenes over the past two decades. However, highlyenantioselective reactions with a broad substrate scope have not yet been developed. We report the first successful example of this reaction employing a catalyst based on a rigid indanol scaffold, which can be easily synthesized from a commercially
Site-Selective 1,1-Difunctionalization of Unactivated Alkenes Enabled by Cationic Palladium Catalysis
作者:Jinwon Jeon、Ho Ryu、Changseok Lee、Dasol Cho、Mu-Hyun Baik、Sungwoo Hong
DOI:10.1021/jacs.9b04142
日期:2019.6.26
β-hydride elimination and migratory insertion with a cationic palladium catalyst. The resulting η3-π-allyl palladium(II) complex is the key intermediate that reacts with a second nucleophile to furnish the desired 1,1-difunctionalization of the alkene. Under the optimized reaction conditions, a wide range of indoles and anilines add to alkene units of 3-butenoic or 4-pentenoic acid derivatives to afford
使用阳离子钯 (II) 配合物开发了钯 (II) 催化的未活化末端和内部烯烃的 1,1-双官能化,通过添加两个亲核试剂。由于亲核试剂与烯烃的区域选择性加成而原位生成的钯环可以很容易地进行区域选择性β-氢化物消除和迁移插入,使用阳离子钯催化剂。所得的 η3-π-烯丙基钯 (II) 络合物是关键中间体,可与第二个亲核试剂反应以提供所需的烯烃 1,1-双官能化。在优化的反应条件下,广泛的吲哚和苯胺添加到 3-丁烯酸或 4-戊烯酸衍生物的烯烃单元中,以提供合成有用的 γ,γ- 或 δ,δ- 双官能化产物,具有优异的区域控制。此外,通过使用内部羟基或酸基团和外部碳亲核试剂,这种转变使不对称的 1,1-双官能化能够形成具有挑战性和重要的氧代季碳中心。结合实验和DFT计算对反应机理进行了详细研究。