Visible-Light-Induced Direct Oxidative C−H Amidation of Heteroarenes with Sulfonamides
作者:Kun Tong、Xiaodong Liu、Yan Zhang、Shouyun Yu
DOI:10.1002/chem.201604014
日期:2016.10.24
A direct oxidative C−H amidation of heteroarenes with sulfonamides via nitrogen‐centered radicals has been achieved. Nitrogen‐centered radicals are directly generated from oxidative cleavage of N−H bonds under visible‐light photoredox catalysis. Sulfonamides, which are easily accessed, are used as tunable nitrogen sources and bleach (aqueous NaClO solution) is used as the oxidant. A variety of heteroarenes
Catalyst-Free Halogenation of α-Diazocarbonyl Compounds with <i>N</i>-Halosuccinimides: Synthesis of 3-Halooxindoles or Vinyl Halides
作者:Chaoqun Ma、Dong Xing、Wenhao Hu
DOI:10.1021/acs.orglett.6b01346
日期:2016.7.1
A novel catalyst-free halogenative cyclization of N-aryl diazoamides with N-halosuccinimides (NXS) is reported for the synthesis of 3-halooxindoles through a carbene-free mechanism. N-Aryl diazoamides reacted with NXS under mild and catalyst-free conditions to afford the corresponding 3-halooxindoles in good yields. This transformation is proposed to proceed through diazonium ion formation followed
3-halooxidation of indoles using DMSO as the oxygen source and NXS (X = Br, Cl) the halo source. This protocol features broad substrate scope and good to excellent yields, thus rendering it as a highly versatile, straightforward, and atom-economical alternative prior to the previously reported methods, which possess their capability to undergo the SN1 substitution of a highly reactiveelectrophilic o-azaxylylene
在这里,我们开发了一种直接有效的协议,用于使用 DMSO 作为氧源和 NXS(X = Br,Cl)作为晕源对吲哚进行 3-卤氧化。该协议具有广泛的底物范围和优良的产量,因此使其成为一种高度通用、直接且原子经济的替代方案,优于先前报道的方法,这些方法具有进行高反应性亲电子物质的 S N 1 取代的能力o -azaxylene中间体生成3, 3-二取代羟吲哚。
AOYAMA H.; OMOTE Y.; HASEGAWA T.; SHIRAISHI H., J. CHEM. SOC. PERKIN TRANS., PART 1 <JCPK-BH>, 1976, NO 14, 1556-1558