Metalation and derivatization of all six dichlorobenzotrifluorides: Site selectivities
The metalation of 2,3-, 2,6-, 2,4- and 3,5-dichlorobenzotrifluorides can be readily effected with std. reagents such as lithium diisopropylamide, lithium 2,2,6,6-tetramethylpiperidide, and butyllithium at the chlorine-adjacent 4- and 3-positions and the chlorine-flanked 3- and 4-positions, resp. However, regioselectivity was secured with 2,6-dichlorobenzotrifluoride only under equilibrating conditions as the initial deprotonation occurs simultaneously at the 3- and 4-positions. 3,4-Dichlorobenzotrifluoride requires methyllithium in the presence of potassium tert-butoxide ("LIM-KOR" mixt.) to undergo regioselective metalation at the 2-position. All the organometallic intermediates were converted into the corresponding benzoic acids by trapping with carbon dioxide, arguably the most popular electrophile for the characterization of organometallic intermediates. [on SciFinder (R)]
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Masson, E., Marzi, E., Cottet, F., Bobbio, C., & Schlosser, M. (2005). Metalation and derivatization of all six dichlorobenzotrifluorides: Site selectivities. European Journal of Organic Chemistry, (20), 4393–4400. https://doi.org/10.1002/ejoc.200500240
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WOS:000232751500022
2005
20
4393
4400
CAN 144:51281 25-17 Benzene, Its Derivatives, and Condensed Benzenoid Compounds Institute of Chemical Sciences and Engineering (ISIC-BCh),Ecole Polytechnique Federale,Lausanne,Switz. Journal 1434-193X written in English. 320-50-3; 320-60-5; 328-84-7; 541-73-1; 54773-19-2; 54773-20-5 Role: RCT (Reactant), RACT (Reactant or reagent) (regioselective metalations and carboxylations of dichlorobenzotrifluorides with lithium reagents); 19230-28-5P; 104359-35-5P; 859794-59-5P; 871254-70-5P; 871254-71-6P; 871254-73-8P; 871254-74-9P; 871254-76-1P; 871254-77-2P; 871254-78-3P; 871254-79-4P; 871254-80-7P; 871254-81-8P; 871254-82-9P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (regioselective metalations and carboxylations of dichlorobenzotrifluorides with lithium reagents); 865-47-4; 917-54-4 (Methyllithium) Role: RGT (Reagent), RACT (Reactant or reagent) (regioselective metalations and carboxylations of dichlorobenzotrifluorides with lithium reagents); 433-97-6P; 454-92-2P; 455-24-3P; 25922-41-2P; 25922-42-3P; 25922-43-4P; 25922-44-5P; 189338-32-7P; 857061-43-9P; 871254-69-2P; 871254-72-7P; 871254-75-0P; 871254-83-0P; 871254-84-1P; 871254-85-2P; 871254-86-3P; 871254-87-4P Role: SPN (Synthetic preparation), PREP (Preparation) (regioselective metalations and carboxylations of dichlorobenzotrifluorides with lithium reagents)
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