Halogen-metal interconversions with halogenated

Halogen-Metal Interconversions with Halo-geneted Anilines. A highly explosive compound which appears to be p-N,N-Trilithioani-line is formed as a by-product in the reaction of BuLi and p-Br-aniline but not o-Br-aniline (Ref 1). More recently this reaction was repeated but no by-product is mentioned (Ref... 

Many organic halides do not react satisfactorily with lithium to form RLi ecMnpounds or with metallic magnesium to form Grignard reagents. The desired organolithium compound can often be prepared by a halogen-metal interconversion reaction ... 

Thiophenedithiol (170) has been prepared by halogen-metal interconversion between the lithium salt of 4-bromo-3-thiophenethiol and n-butyllithium at —70°C, followed by reaction with sulfur/ IR, NMR, and UV spectra showed that this compound exists in the dithiol form (170). The compound obtained as a by-product in the... 

Halogen-metal interconversion between bromothiophenes and n -butyllithium occurs almost instantaneously and in very high yield. The reaction with 3-bromothiophene is usually carried out at -70 °C to avoid any (rans-lithiation. When bromine-lithium exchange takes place, steric crowding in the molecule decreases. As a consequence the percentage of 2-lithio derivative in relation to the 5-lithio isomer formed from 3-alkyl-2,5-... 

R. G. Jones, H. Gilman, The Halogen-Metal Interconversion Reaction with Organolithium Compounds, ... 

The halogen-metal interconversion reaction with organolithium compounds... 

The Halogen-Metal Interconversion Reaction with Organolithium Compounds ... 

By halogen-metal interconversion, Murray et al. prepared nicotinic acid labeled with i C (82% yield) or (62% yield) on the carboxyhc radical. Using M-butyl lithium and 3-bromopyridine, 3-pyridyl hthium was prepared and carbonation of this compound was carried out with i C02 or COa generated from the respective labeled barium carbonates with acid. 

The Gihnan-Swiss test, or Color Test II [151], is specific to alkyllithium reagents. Here, a halogen-metal interconversion in presence of an alkyllithium compound occurs with 4-bromo-iV,iV-dimethylaniline 70. After addition of benzophenone and, a few minutes later, concentrated hydrochloric acid, a bright red color for the triaryhnethyl cation 71 appears (Scheme 26.20). 

The halogen-metal interconversion, using organolithium compounds , also presents a problem of classification. One representation of its progress , shown below, makes it in one sense an electrophilic substitution, and with a clear recognition of the ambiguity, we shall for classification purposes regard it as such. 

---