The acidifying effects of chlorine and bromine: little difference

Lithium diisopropylamide deprotonates o- and p-bromochlorobenzene randomly at the two halogen adjacent positions. Obviously for steric reasons, the bulkier base lithium 2,2,6,6-tetramethylpiperidide favors the attack in the vicinity of the chlorine rather than the bromine atom to the extent of 2:1. At -75 DegC, both 2-bromo-3-chlorophenyllithium and 3-bromo-2-chlorophenyllithium isomerize to give 2-bromo-6-chlorophenyllithium. The latter species can be directly generated from 1-bromo-3-chlorobenzene. [on SciFinder (R)]


Published in:
Tetrahedron Letters, 38, 9, 1559-1562
Year:
1997
Keywords:
Note:
CAN 126:250940
25-3
Benzene, Its Derivatives, and Condensed Benzenoid Compounds
Inst. Chim. Org.,Univ. Batiment Chim.,Lausanne-Dorigny,Switz.
Journal
0040-4039
written in English.
106-39-8 (p-Bromochlorobenzene); 108-37-2 (m-Bromochlorobenzene); 694-80-4 (o-Bromochlorobenzene); 4111-54-0 (Lithium diisopropylamide); 38227-87-1 (Lithium 2,2,6,6-tetramethylpiperidide) Role: RCT (Reactant), RACT (Reactant or reagent) (effects of bromo and chloro substituents on deprotonation of bromochlorobenzenes); 633-12-5P; 21739-92-4P; 21739-93-5P; 56961-26-3P; 56961-27-4P; 65410-81-3P; 93224-85-2P; 188663-74-3P Role: SPN (Synthetic preparation), PREP (Preparation) (effects of bromo and chloro substituents on deprotonation of bromochlorobenzenes)
Laboratories:




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


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