Promoting or preventing haloaryllithium isomerizations: differential basicities and solvent effects as the crucial variables
Deprotonation-triggered heavy halogen migrations should become a favorite tool in arene synthesis if their occurrence and outcome could be made predictable. Particularly attractive, though extremely rare, are stop-and-go situations where a first intermediate, generated by metalation, can be trapped at -100 DegC, whereas at -75 DegC halogen migration gives rise to an isomer. As shown now, one can conveniently produce the initial aryllithium species by halogen/metal interconversion in toluene at -100 DegC, under conditions that preclude halogen migration, and unleash the isomerization process by adding THF at -75 DegC. [on SciFinder (R)]
WOS:000227774800020
2005
4
617
621
CAN 142:446967
25-17
Benzene, Its Derivatives, and Condensed Benzenoid Compounds
Institute of Chemistry and Molecular Sciences,Ecole Polytechnique Federale, BCh,Lausanne,Switz.
Journal
written in English.
111771-08-5P (2-Fluoro-6-iodobenzoic acid) Role: BYP (Byproduct), RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (haloaryllithium isomerizations in arene synthesis based on differential basicities and solvent effects); 372-18-9 (1,3-Difluorobenzene); 462-06-6 (Fluorobenzene); 1073-06-9 (1-Bromo-3-fluorobenzene); 1121-86-4 (1-Fluoro-3-iodobenzene); 13697-89-7 (1,3-Difluoro-2-iodobenzene); 64248-56-2 Role: RCT (Reactant), RACT (Reactant or reagent) (haloaryllithium isomerizations in arene synthesis based on differential basicities and solvent effects); 2252-37-1P; 38361-37-4P; 132715-69-6P; 154257-75-7P; 647020-71-1P; 851368-02-0P; 851368-03-1P; 851368-04-2P; 851368-05-3P; 851368-06-4P; 851368-08-6P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (haloaryllithium isomerizations in arene synthesis based on differential basicities and solvent effects); 1583-58-0P; 28314-81-0P; 146014-66-6P; 229178-74-9P; 820236-81-5P; 851368-07-5P Role: SPN (Synthetic preparation), PREP (Preparation) (haloaryllithium isomerizations in arene synthesis based on differential basicities and solvent effects)
REVIEWED
EPFL