Publication

Reagent-modulated optional site selectivities: the metalation of o-, m- and p-halobenzotrifluorides

Manfred Schlosser
1996
Journal Articles

Abstract

Chloro(trifluoromethyl)benzenes and bromo(trifluoromethyl)benzenes underwent deprotonation at a postion adjacent to the single halogen substituent when treated with alkyllithiums (at -75 DegC) and, resp., lithium 2,2,6,6-tetramethylpiperidide (at -100 DegC) in THF. Positional ambiguities, if existing, were be exploited to establish optional site selectivities. Thus, the reaction of butyllithium with 1-chloro-3-(trifluoromethyl)benzene led to hydrogen/metal interconversion at the 2-position whereas the reaction of sec-butyllithium led exclusively to a reaction at the 6-position. The latter mode of regioselectivity was also exhibited by 1-bromo-3-(trifluoromethyl)benzene in the presence of lithium 2,2,6,6-tetrmethylpiperidide, and only 2-bromo-4-(trifluoromethyl)phenyllithium was produced. 2-Bromo-6-(trifluoromethyl)phenyllithium was directly inaccessible, but was formed when 2-bromo-3-(trifluoromethyl)phenyllithium, (generated at -100 DegC) was allowed to isomerize at -75 DegC. [on SciFinder (R)]

Official source

https://infoscience.epfl.ch/entities/publication/c1674f0f-debd-4b36-a132-6a00e131fe56

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Manfred Schlosser
1996
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/c1674f0f-debd-4b36-a132-6a00e131fe56

About this result

Related concepts (15)

Tert-Butyllithium

tert-Butyllithium is a chemical compound with the formula (CH3)3CLi. As an organolithium compound, it has applications in organic synthesis since it is a strong base, capable of deprotonating many carbon molecules, including benzene. tert-Butyllithium is available commercially as hydrocarbon solutions; it is not usually prepared in the laboratory. tert-Butyllithium is produced commercially by treating tert-butyl chloride with lithium metal. Its synthesis was first reported by R. B. Woodward in 1941.

Organolithium reagent

In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom to the substrates in synthetic steps, through nucleophilic addition or simple deprotonation. Organolithium reagents are used in industry as an initiator for anionic polymerization, which leads to the production of various elastomers.

N-Butyllithium

n-Butyllithium C4H9Li (abbreviated n-BuLi) is an organolithium reagent. It is widely used as a polymerization initiator in the production of elastomers such as polybutadiene or styrene-butadiene-styrene (SBS). Also, it is broadly employed as a strong base (superbase) in the synthesis of organic compounds as in the pharmaceutical industry. Butyllithium is commercially available as solutions (15%, 25%, 1.5 M, 2 M, 2.5 M, 10 M, etc.) in alkanes such as pentane, hexanes, and heptanes.