Regioselective ortho-lithiation of chloro- and bromo-substituted fluoroarenes
Deprotonation of fluoroarenes carrying chlorine or bromine as addnl. substituents occurred always at a position adjacent to a fluorine if accomplished with potassium tert-butoxide activated butyllithium or lithium 2,2,6,6-tetramethylpiperidide. For example, treatment of 1-chloro-4-fluorobenzene with potassium tert-butoxide/butyllithium (superbase reagent) gave 5-chloro-2-fluorobenzoic acid (86% yield) as the major product and a small amt. of 2-chloro-5-fluorobenzoic acid. [on SciFinder (R)]
1996
37
36
6551
6554
CAN 125:300552
25-17
Benzene, Its Derivatives, and Condensed Benzenoid Compounds
Batiment Chimie,Inst. Chimie Organique Universite,Lausanne-Dorigny,Switz.
Journal
written in English.
394-28-5P; 2252-50-8P Role: BYP (Byproduct), PREP (Preparation) (prepn. of benzene derivs. by regioselective lithiation of chlorofluorobenzene or bromofluorobenzene); 348-51-6 (1-Chloro-2-fluorobenzene); 348-61-8 (4-Bromo-1,2-difluorobenzene); 352-33-0 (1-Chloro-4-fluorobenzene); 460-00-4 (1-Bromo-4-fluorobenzene); 461-96-1 (5-Bromo-1,3-difluorobenzene); 625-98-9 (1-Chloro-3-fluorobenzene); 1072-85-1 (1-Bromo-2-fluorobenzene); 1073-06-9 (1-Bromo-3-fluorobenzene); 1435-53-6 (1,3-Dibromo-4-fluorobenzene); 38227-87-1 (Lithium 2,2,6,6-tetramethylpiperidide); 183065-70-5 Role: RCT (Reactant), RACT (Reactant or reagent) (prepn. of benzene derivs. by regioselective lithiation of chlorofluorobenzene or bromofluorobenzene); 394-30-9P; 434-75-3P; 2252-37-1P; 146328-85-0P; 161957-55-7P; 161957-56-8P; 183065-68-1P; 183065-69-2P; 183065-71-6P; 183065-72-7P; 183065-73-8P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of benzene derivs. by regioselective lithiation of chlorofluorobenzene or bromofluorobenzene); 109-72-8 (Butyllithium); 865-47-4 (Potassium tert-butoxide) Role: RCT (Reactant), RACT (Reactant or reagent) (superbase reagent; prepn. of benzene derivs. by regioselective lithiation of chlorofluorobenzene or bromofluorobenzene)
REVIEWED
EPFL