Photocatalytic Vicinal Aminopyridylation of Methyl Ketones by a Double Umpolung Strategy
作者:Honggu Im、Wonjun Choi、Sungwoo Hong
DOI:10.1002/anie.202008435
日期:2020.9.28
umpolung strategy for the vicinal aminopyridylation of ketones was developed using pyridinium N−N ylides. The inversion of the polarity of the pyridinium N−N ylides by single‐electron oxidation successfully enables radical‐mediated 1,3‐dipolar cycloadditions with enolsilanes formed in situ from ketones, followed by homolytic cleavage of the N−N bond. Intriguingly, the nucleophilic amino and electrophilic
Iron-Catalyzed Highly Enantioselective Addition of Silyl Enol Ethers to α,β-Unsaturated 2-Acyl Imidazoles
作者:Jinhu Wei、Jie-Sheng Huang、Chi-Ming Che
DOI:10.1021/acs.orglett.1c02699
日期:2021.9.3
FeII(N4) complex (N4 = (R,R)-N,N′-bis(2-isopropylquinolin-8-yl)-1,2-diphenylethane-1,2-diamine) was developed for the asymmetric conjugate addition of silyl enol ethers, including both acyclic ones and cyclohexenone-derived ones, to α,β-unsaturated 2-acyl imidazoles. This FeII complex is an effective chiral Lewis acid and was applied in the synthesis of an array of chiral 1,5-dicarbonyl synthons and cyclohexenone
开发了手性 Fe II (N4) 配合物 (N4 = ( R , R )- N , N '-bis(2-isopropylquinolin-8-yl)-1,2-diphenylethane-1,2-diamine) 用于不对称甲硅烷基烯醇醚(包括无环和环己烯酮衍生的)与 α,β-不饱和 2-酰基咪唑的共轭加成。这种 Fe II 配合物是一种有效的手性路易斯酸,用于合成一系列手性 1,5-二羰基合成子和环己烯酮衍生物,具有高产率和对映选择性(高达 99% ee)。
Sunlight-driven synthesis of γ-diketones via oxidative coupling of enamines with silyl enol ethers catalyzed by [Ru(bpy)3]2+
作者:Yusuke Yasu、Takashi Koike、Munetaka Akita
DOI:10.1039/c2cc31748f
日期:——
A photosensitizer [Ru(bpy)3]2+ catalyzes oxidative coupling reaction of enamines with silyl enol ethers under visible light irradiation by a Xe lamp or sunlight to produce γ-diketones. A 2e-oxidation process involved in this reaction is achieved by a combination of the photoexcited [Ru(bpy)3]2+ species and duroquinone, a 2e-acceptor.
A novel Rh(II)-catalyzed transannulation of 1-tosyl-1,2,3-triazoles with silyl or alkyl enolethers has been developed, which enables the facile synthesis of substituted pyrroles in a regiocontrollable manner. Moreover, the methodology could be extended to access 3-pyrrolin-2-one derivatives with silyl ketene acetals used as the reaction partner.
Aniline‐Promoted Cyclization–Replacement Cascade Reactions of 2‐Hydroxycinnamaldehydes with Various Carbonic Nucleophiles through In Situ Formed
<i>N</i>
,
<i>O</i>
‐Acetals
作者:Chenguang Yu、He Huang、Xiangmin Li、Yueteng Zhang、Hao Li、Wei Wang
DOI:10.1002/chem.201601112
日期:2016.6.27
of N,O‐acetals in an aminocatalytic fashion for organic synthesis. Unlike widely used strategies requiring the use of acids and/or elevated temperatures, direct replacement of the amine component of the N,O‐acetals by carbon‐centered nucleophiles for C−C bondformation is realized under mild reaction conditions. Furthermore, without necessary preformation of the N,O‐acetals, an amine‐catalyzed in situ