Tetrahedron letters

Competitive ortho metalation effects: The kinetic and thermodynamic lithiation of 3-(tert-butoxycarbonyl) amino-4-carbomethoxythiophene

WA Carroll, X Zhang

Index: Carroll, William A.; Zhang, Xiaolin Tetrahedron Letters, 1997 , vol. 38, # 15 p. 2637 - 2640

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Citation Number: 6

Abstract

Deprotonation of the thiophene 1 under kinetically controlled conditions with LDA takes place next to the NHBoc group and under thermodynamic conditions next to the methyl ester. N-Methylation leads to exclusive lithiation next to the ester. The methyl ester was found to be superior to the diethylamide in facilitating lithiation.