TEMPO 催化的交叉二卤化反应是通过氧化还原调节双亲电 X +试剂的复杂系统而建立的。形式上,ICl的,氯化溴,我2和Br 2产生在-原位,这使高区域选择性或立体选择性获得的iodochlorination,bromochlorination和均-二卤化产物无数与功能性的宽光谱。该方法条件温和,操作简单,可广泛应用于有机合成,例如两种药物的发散合成。通过详细的机械调查进行了自由基钟反应、频哪醇扩环和哈米特实验,证实了卤离子的中介作用。此外,提出了一种基于 TEMPO 多功能催化作用的动态催化模型来解释选择性结果。
Direct Conversion of Carbonyl Compounds into Organic Halides: Indium(III) Hydroxide-Catalyzed Deoxygenative Halogenation Using Chlorodimethylsilane
作者:Yoshiyuki Onishi、Daigo Ogawa、Makoto Yasuda、Akio Baba
DOI:10.1021/ja0283246
日期:2002.11.1
the corresponding deoxygenativechlorination products, in which the carbonyl carbon accepted two nucleophiles (H and Cl) with releasing oxygen. Only In(OH)3 catalyzed the reaction, and typical Lewis acids such as TiCl4, AlCl3, and BF3.OEt2 showed no catalytic activity. The reaction mechanism of this deoxygenativechlorination includes initial hydrosilylation followed by chlorination. Other nucleophiles
An easy method for epoxidation of olefins using bleach (sodium hypochlorite) and either a stoichiometric or catalytic amount of bromide ion has been developed. Without any transition metal catalyst a variety of non-activated olefins give epoxides in high yields and good selectivity at ambient conditions.
Bromochlorination of Alkenes with Dichlorobromate(1−) Ion. V. Regio- and Stereochemistry for the Bromochlorination of Styrene Derivatives with Dichlorobromate(1−) Ion in Protic Solvents
作者:Takeshi Negoro、Yoshitsugu Ikeda
DOI:10.1246/bcsj.59.3519
日期:1986.11
bromochlorination of styrene derivatives with tetrabutylammonium dichlorobromate(1−) (1) in such protic solvents as acetic acid and methanol gives the corresponding bromo chloro adducts along with substantial amounts of solvent-incorporated products in a regiospecific manner (regioselective in the case of 3-nitro- or 2-chlorostyrenes). The reaction of 1-phenylpropenes with 1 gives nonstereospecific but regiospecific