Tetrahedron

High-yielding syntheses of 4 (5)-substituted imidazoles via organolithium intermediates. the utility of sulphonamide n-protection and silicon-containing blocking groups

AJ Carpenter, DJ Chadwick

Index: Carpenter, Andrew J.; Chadwick, Derek J. Tetrahedron, 1986 , vol. 42, # 8 p. 2351 - 2358

Full Text: HTML

Citation Number: 57

Abstract

N-Protection of imidazole as its N, N-dimethyl-sulphonamido derivative, and blocking of the 2-position with the triethylsilyl group permits regioselective 5-metallation with sec-butyl- lithium. The resulting organolithium intermediates react with a range of electrophiles and the products are easily deprotected to give the 4 (5)-substituted NH-free imidazoles in good to excellent yields. Isolation of the silicon-blocked intermediate is unnecessary and, indeed, ...