Organometallic Reactions of ι-Fluoroalkyl Halides. I.¹ Preparation of ι-Fluoroalkylmagnesium Halides

Abstract

Optimum conditions have been determined for the preparation of various -fluoroalkylmagnesium halides. The effects of halogen and chain-length on the course of the reactions were investigated. A series of -fluorocarboxylic acids were prepared by carbonation of the Grignard reagents.

Organic Fluorine Chemistry

“…Nevertheless, some instances of halogenmetal interconversion were noticed in the preparation of Grignard reagents from a,w-fluorohaloparaffins. Such a reaction is responsible for the occurrence of w-haloalkanecarboxylic acids and a,w-dicarboxylic acids in addition to the expected w-fluoroalkanecarboxylic acids after the treatment of the reaction mixture with carbon dioxide (451]. (272) (451) In the aromatic series, a Grignard reagent was easily prepared from m-bromobenzotrifluoride [452].…”

“…Such a reaction is responsible for the occurrence of w-haloalkanecarboxylic acids and a,w-dicarboxylic acids in addition to the expected w-fluoroalkanecarboxylic acids after the treatment of the reaction mixture with carbon dioxide (451]. (272) (451) In the aromatic series, a Grignard reagent was easily prepared from m-bromobenzotrifluoride [452]. If the fluorine atom is in o-position to bromine, the reaction with magnesium results in the formation of dehydrobenzene (benzyne) (p. 127).…”

Reactions of Fluoroalkanes with Mg−Mg Bonds: Scope, sp3C−F/sp2C−F Coupling and Mechanism

“…Fluorocarbons are often considered inert toward Grignard formation. There is, however, a series of somewhat contradictory reports that metallic magnesium can be used to generate Grignard reagents from fluoroalkanes, provided a suitable initiator (e.g., I 2 , Br 2 , EtBr) is present . Captivated by these studies, we became interested in the reactivity of 1 a towards fluoroalkanes.…”

Grignard reagent formation via C–F bond activation: a centenary perspective

“…An experimental demonstration of counterintuitive reactivity was provided in 1956 by Pattison and Howell. 20 Hence, fluorohexane derivatives of general formula F–(CH 2 ) 6 –X (X = Cl, Br, I) were reacted with activated magnesium followed by quenching with carbon dioxide (Scheme 1b). Interestingly, the highest yields of the carboxylic acid resulting from C–X bond cleavage (F–(CH 2 ) 6 –COOH) were obtained in the case when X = Cl.…”