Tetrahedron letters

A Study of the Lithiation of 2, 6-Dibromopyridine with Butyllithium, and its Application to Synthesis of L-739,010

D Cai, DL Hughes, TR Verhoeven

Index: Cai, Dongwei; Hughes, David L.; Verhoeven, Thomas R. Tetrahedron Letters, 1996 , vol. 37, # 15 p. 2537 - 2540

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Citation Number: 84

Abstract

Mono-lithiation of 2, 6-dibromopyridine by n-BuLi is complicated by deprotonation of the pyridine ring by the resulting mono-lithium species. This problem can be eliminated by a reverse addition, but this causes formation of the undesired dilithio species. However, rapid lithium-halogen exchange between 2, 6-dibromopyridine and 2, 6-dilithiopyridine produces 2-bromo-6-lithiopyridine cleanly. Thus, using reverse addition, the mono-lithiated pyridine ...