1,2,4-Tris(trifluoromethyl)benzene: selective lithiation and subsequent electrophilic substitution

1,2,4-Tris(trifluoromethyl)benzene quant. undergoes a hydrogen/metal exchange when treated with an ethereal soln. of lithium 2,2,6,6-tetramethylpiperidide. Proton abstraction occurs concomitantly from positions 5 and 6, the ratios varying from 80:20 to 90:10, depending on the reaction conditions. Pure 5-iodo-1,2,4-tris(trifluoromethyl)benzene was readily obtained by fractional crystn. of the regioisomeric mixt. and was used to prep. 5-substituted derivs. of 1,2,4-tris(trifluoromethyl)benzene by consecutive reaction with tert-butyllithium and an electrophile. [on SciFinder (R)]


Published in:
Tetrahedron, 54, 5/6, 895-900
Year:
1998
Keywords:
Note:
CAN 128:140479
25-3
Benzene, Its Derivatives, and Condensed Benzenoid Compounds
Inst. Chim. Org. Univ. Batiment Chim,Lausanne-Dorigny,Switz.
Journal
0040-4020
written in English.
393-05-5 (1,2,4-Tris(trifluoromethyl)benzene); 38227-87-1 (Lithium 2,2,6,6-tetramethylpiperidide) Role: RCT (Reactant), RACT (Reactant or reagent) (lithiation and electrophilic substitution of tris(trifluoromethyl)benzene); 202465-19-8P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (lithiation and electrophilic substitution of tris(trifluoromethyl)benzene); 202465-23-4P; 202465-24-5P Role: SPN (Synthetic preparation), PREP (Preparation) (lithiation and electrophilic substitution of tris(trifluoromethyl)benzene); 202465-18-7P; 202465-20-1P; 202465-21-2P; 202465-22-3P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of)
Laboratories:




 Record created 2006-03-03, last modified 2018-01-27


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