Benzyl Radicals from Toluene by Photosensitization with Naphthalene-1,4-dicarbonitrile – Benzylation and Hydroxymethylation of Unsaturated Compounds
作者:Mariella Mella、Maurizio Fagnoni、Angelo Albini
DOI:10.1002/(sici)1099-0690(199909)1999:9<2137::aid-ejoc2137>3.0.co;2-r
日期:1999.9
transfer from toluene to 1,4-naphthalenedicarbonitrile (DCN) is followed by in-cage proton transfer and radical coupling. However, in the presence of a protic co-solvent, the radical ions diffuse out of the cage and deprotonation of the toluene radical cation takes place from the free solvated species. With tBuOH, this results in reductive benzylation of DCN through coupling of benzyl radicals with DCN–·
在非质子介质中,光诱导电子从甲苯转移到 1,4-萘二甲腈 (DCN) 之后是笼内质子转移和自由基偶联。然而,在质子共溶剂的存在下,自由基离子扩散出笼子,并且甲苯自由基阳离子从游离溶剂化物质中发生去质子化。使用 tBuOH,这会通过苄基自由基与 DCN-· 的偶联导致 DCN 的还原性苄基化。使用 MeOH,PhCH2· 二次夺氢产生羟甲基自由基,其与 DCN-· 偶联。苄基和羟甲基自由基都被亲电烯烃有效捕获。因此,在马来酸二甲酯存在下,底物的 DCN 光敏化苄基化(或羟甲基化)是通过直接激活 C-H 键而发生的。