A simple method for the displacement of bromine by fluorine at tertiary, benzylic or non-classical secondary sites
Using in situ generated iodine fluoride as the reagent, bromine can be replaced by fluorine at carbocation-sustaining sites. Iodine fluoride or, being its operational equiv., the mixt. of N-iodosuccinimide and triethylamine tris(hydrogen fluoride) reacts with tertiary and benzylic bromoalkanes to afford the resp. fluoroalkanes in moderate-to-excellent yields. In contrast, primary bromoalkanes are virtually inert under identical conditions. Secondary bromoalkanes do not react either unless the heterolytically generated cationic intermediates benefit from non-classical resonance stabilization. [on SciFinder (R)]
WOS:000179152200015
2002
117
2
177
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CAN 138:271297 25-3 Benzene, Its Derivatives, and Condensed Benzenoid Compounds Institut de Chimie Moleculaire et Biologique, Department de Chimie,Ecole Polytechnique Federale,Lausanne,Switz. Journal 0022-1139 written in English. 626-87-9 (1,4-Dibromopentane); 637-59-2 ((3-Bromopropyl)benzene); 2404-35-5 (Bromocycloheptane) Role: RCT (Reactant), RACT (Reactant or reagent) (failed reaction; prepn. of fluoroalkanes by chemoselective, stereoselective displacement of bromine at tertiary, benzylic or non-classical secondary sites using iodine fluoride); 503537-97-1P (4-Bromo-1-octene) Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (failed reaction; prepn. of fluoroalkanes by chemoselective, stereoselective displacement of bromine at tertiary, benzylic or non-classical secondary sites using iodine fluoride); 79-92-5 (Camphene); 40386-14-9 ((1R,2R,4R)-rel-2-Bromo-1-(bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptane) Role: RCT (Reactant), RACT (Reactant or reagent) (prepn. of (bromomethyl)fluorodimethylbicycloheptane by chemoselective, stereoselective displacement of bromine in bromo(bromomethyl)dimethylbicycloheptane using iodine fluoride); 51361-76-3P ((1R,2S,4S)-rel-1-(Bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-ol); 220306-18-3P; 220306-19-4P; 503537-94-8P ((1R,2S,4S)-rel-1-(Bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-ol acetate); 503537-95-9P ((1R,2S,4S)-rel-1-(Bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-ol trifluoroacetate); 503537-96-0P ((1R,2S,4S)-rel-1-(Bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-ol 4-methylbenzenesulfonate) Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of (bromomethyl)fluorodimethylbicycloheptane by chemoselective, stereoselective displacement of bromine in bromo(bromomethyl)dimethylbicycloheptane using iodine fluoride); 64-19-7 (Acetic acid); 75-69-4 (Trichlorofluoromethane); 76-05-1 (Trifluoroacetic acid); 104-15-4 (4-Methylbenzenesulfonic acid); 106-95-6 (3-Bromo-1-propene); 110-62-3 (Pentanal); 516-12-1 (N-Iodosuccinimide); 585-71-7 ((1-Bromoethyl)benzene); 768-90-1 (1-Bromoadamantane); 776-74-9 (1,1'-(Bromomethylene)bis[benzene]); 2534-77-2; 7553-56-2 (Iodine); 73602-61-6 (Triethylamine tris(hydrogen fluoride) Role: RCT (Reactant), RACT (Reactant or reagent) (prepn. of fluoroalkanes by chemoselective, stereoselective displacement of bromine at tertiary, benzylic or non-classical secondary sites using iodine fluoride); 13873-84-2P (Iodine fluoride (IF); 40575-42-6P (1-Octen-4-ol) Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. of fluoroalkanes by chemoselective, stereoselective displacement of bromine at tertiary, benzylic or non-classical secondary sites using iodine fluoride); 579-55-5P (1,1'-(Fluoromethylene)bis[benzene]); 765-92-4P ((1R,2R,4S)-rel-2-Fluorobicyclo[2.2.1]heptane); 768-92-3P (1-Fluoroadamantane); 7100-97-2P ((1-Fluoroethyl)benzene) Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of fluoroalkanes by chemoselective, stereoselective displacement of bromine at tertiary, benzylic or non-classical secondary sites using iodine fluoride)
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