Tetrahedron letters

The acidifying effects of chlorine and bromine: Little difference

F Mongin, M Schlosser

Index: Mongin, Florence; Schlosser, Manfred Tetrahedron Letters, 1997 , vol. 38, # 9 p. 1559 - 1562

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Citation Number: 35

Abstract

Lithium diisopropylamide deprotonates ortho-and para-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° C, both 2-bromo-3-chlorophenyllithium and 3- bromo-2-chlorophenyllithium isomerize to give 2-bromo-6-chlorophenyllithium. The latter ...