通过时间分辨光谱研究了在过硫酸铵存在下有机/水混合物中的芳基甲磺酸酯和芳基二乙基磷酸酯的单电子氧化。光生 SO 4 ˙ -自由基阴离子和被检测底物之间的光致电子转移 (ET)显示速率常数 ( k ET ) 约为 10 9 –10 10 M -1 s -1并且生成的自由基阳离子表现出宽吸收带(350-550 nm),寿命值在 7-62 μs 范围内,具体取决于芳族取代基的性质。log ( k ET ) 和 Δ之间的相关性令人满意G 0 ET证明了 ET 过程遵循 Marcus 模型。
Irradiation of electron-donating substituted phenyl halides (fluorides and chlorides) or esters (mesylates, triflates and phosphates) in aqueous MeCN in the presence of KCN gives the corresponding benzonitriles in 48 to 100% yield through an ArSN1 reaction with the intermediacy of a triplet phenyl cation.
A convenient photochemical flow protocol for the formation of aryl‐carbon bonds via photogenerated phenyl cations has been developed. A wide range of phenylated products, including biaryls, allylarenes, 2‐arylacetals and benzyl γ‐lactones, was smoothly synthesized in satisfactory yields under metal‐free conditions. The adoption of a flow reactor often allowed us to adopt higher concentrations of substrates
van Hooidonk,C.; Ginjaar,L., Recueil des Travaux Chimiques des Pays-Bas, 1967, vol. 86, p. 449 - 457
作者:van Hooidonk,C.、Ginjaar,L.
DOI:——
日期:——
Benzyl (Phenyl) γ- and δ-lactones via Photoinduced Tandem Ar−C, C−O Bond Formation
作者:Stefano Protti、Maurizio Fagnoni、Angelo Albini
DOI:10.1021/ja0627287
日期:2006.8.1
A convenient metal-free procedure for the preparation of benzyl (phenyl) gamma- and delta-lactones is illustrated. This method is based on the photochemical generation of phenyl cations and their reaction with 3, 4, or 5-alkenoic acids. This leads to a phenyl- or benzyl-substituted lactone by tandem formation of an aryl-C and C-O bond. The intermediacy of a phenonium ion imparts a full regio- and stereoselectivity to the reaction.
Metal-Free Synthesis of Sterically Crowded Biphenyls by Direct ArH Substitution in Alkyl Benzenes