Synthesis of 1,4‐Dicarbonyl Compounds by Visible‐Light‐Mediated Cross‐Coupling Reactions of α‐Chlorocarbonyls and Enol Acetates
作者:Qiang Liu、Rui‐Guo Wang、Hong‐Jian Song、Yu‐Xiu Liu、Qing‐Min Wang
DOI:10.1002/adsc.202000791
日期:2020.10.21
visible‐light‐mediatedradical coupling reactions of α‐chloroketones and enol acetates to afford 1,4‐dicarbonyl compounds, which are important precursors and intermediates in organic synthesis. The reaction involves photoredox‐catalyzed activation of the α‐chloroketone upon photoelectron transfer, carbon–chlorine bond cleavage, and coupling of the resulting radical with the carbon–carbon double bond of the
Catalytic Asymmetric (3 + 3) Cycloaddition of Oxyallyl Zwitterions with α-Diazomethylphosphonates
作者:Yan Liu、Xian Peng、Rui She、Xin Zhou、Yungui Peng
DOI:10.1021/acs.orglett.1c02809
日期:2021.9.17
The unique structure of oxyallyls represents a significant challenge for their catalyticasymmetric applications. Herein, an unprecedented chiral imidodiphosphoric acid-catalytic enantioselective (3 + 3) cycloaddition between oxyallyl zwitterions generated in situ from α-haloketones and α-diazomethylphosphonates was developed. Pharmaceutically interesting chiral pyridazine-4(1H)-ones were obtained
A diastereoselective (3 + 2) dearomativeannulation of 3-substituted indoles with α-haloketones has been developed. Significant regiochemical control was observed. This methodology provides easy access to highly functionalized cyclopenta- or cyclohexa-fused indoline compounds, which are common structures of many natural products. The synthetic potential of this reaction was demonstrated in the concise
Catalyst-free formation of 1,4-diketones by addition of silyl enolates to oxyallyl zwitterions in situ generated from α-haloketones
作者:Juan Luo、Qihua Jiang、Hao Chen、Qiang Tang
DOI:10.1039/c5ra12244a
日期:——
IV. Thus, a variety of metal-catalyzed coupling reactions have been developed to avoid the undesired reaction when attempting the preparation of 1,4-diketones. We found that the oxyallylzwitterions in situ generatedfrom α-haloketones enabled the addition of silyl enolates to the α-carbonyl position to exclusively form 1,4-diketones in weakly basic conditions. Various types of silyl enolates and α-haloketones
Addition of Indoles to Oxyallyl Cations for Facile Access to α-Indole Carbonyl Compounds
作者:Qiang Tang、Xingkuan Chen、Bhoopendra Tiwari、Yonggui Robin Chi
DOI:10.1021/ol300591z
日期:2012.4.6
A direct coupling of unprotected indoles and α-halo ketones via in situ generated oxyallyl cation intermediates is described. The reactions efficiently afford α-indole carbonyl compounds with good to quantitative yields.