Mild and Efficient α-Chlorination of Carbonyl Compounds Using Ammonium Chloride and Oxone (2KHSO<sub>5</sub>·KHSO<sub>4</sub>·K<sub>2</sub>SO<sub>4</sub>)
A simple protocol for the α-monochlorination of ketones and 1,3-dicarbonyl compounds utilizing NH4Cl as a source of chlorine and Oxone as an oxidant in methanol without catalyst is presented. The reaction proceeds at ambient temperature in yields ranging from moderate to excellent.
new protocol for the direct two-electron oxidative Umpolung of alkali halidesalts is reported. This procedure, relying on the use of a commercially available sulfoxide as the oxidant, allows the electrophilichalogenation of carbonyl compounds as well as halolactonisation reactions to proceed from the corresponding sodium salts, at room temperature and under mild conditions.
作者:Shelli R. Mellegaard-Waetzig、Chao Wang、Jon A. Tunge
DOI:10.1016/j.tet.2005.12.072
日期:2006.7
Organoselenides catalyze the oxidation of halides by H2O2. Furthermore, these selenides catalyze the transfer of oxidized halogens from N-halosuccinimides to olefins and ketones. Thus, organoselenides catalyze oxidative halogenation reactions including halolactonization, α-halogenation of ketones, and allylic halogenation. The ability of selenium to undergo reversible 2e− oxidation–reduction chemistry
有机硒化物通过H 2 O 2催化卤化物的氧化。此外,这些硒化物催化氧化的卤素从N-卤代琥珀酰亚胺向烯烃和酮的转移。因此,有机硒化物催化氧化卤化反应,包括卤代内酯化,酮的α-卤化和烯丙基卤化。硒的能力经历可逆2E -氧化-还原化学功能有助于卤化硒通过绑定卤中间体。
A green approach for efficient α-halogenation of β-dicarbonyl compounds and cyclic ketones using N-halosuccinimides in ionic liquids
Room temperature ionic liquids (ILs) are used as a green recyclable reaction media for the α-monohalogenation of 1,3-diketones, β-keto-esters and cyclic ketones with N-halosuccinimides in excellent yields in the absence of a catalyst. The recovered ionic liquid was reused five to six times with consistent activity.
Hydrogen Peroxide or Peracetic Acid Mediated Self-Titrating α-Halogenation of 1,3-Dicarbonyl Compounds
作者:Hasim Ibrahim、Ramulu Akula、Marc Galligan
DOI:10.1055/s-0030-1258367
日期:2011.1
Efficient oxidative α-halogenation of 1,3-dicarbonylcompounds has been achieved by employing a system comprising of sub-stoichiometric amounts of TiX4 (X = Cl, Br) in conjunction with environmentally benign hydrogen peroxide (H2O2) or peracetic acid (MeCO3H) as the oxidants. The end point of the reaction is accompanied by a sharp colour change. halogenation - peroxides - titanium - halides - electrophilic
通过使用包含亚化学计量量的TiX 4(X = Cl,Br)以及环境友好的过氧化氢(H 2 O 2)或过氧乙酸的系统,可以实现1,3-二羰基化合物的有效氧化α-卤化酸(MeCO 3 H)作为氧化剂。反应的终点伴随着急剧的颜色变化。 卤化-过氧化物-钛-卤化物-亲电子