Pyrrole 2- lithio-1-methyl

Substituted pyrroles do not react with Grignard reagents or alkali metals, but 1-methyl and 1-phenylpyrrole have been reported to react with w-butyllithium to give the a-lithio derivative.218... 

N-methyl pyrrole 2.34, thiophene, and furan can be metallated at the C2 position with alkyl lithium reagents. This position is more activated to deprotonation than the C3 position because of the electron-withdrawing inductive effect of the heteroatom. The nucleophilic 2-lithio species can then be reacted with various electrophiles, as in the preparation of 2.37, 2.38,... 

V-Benzylthieno[3,2-6]pyrrole (18) was lithiated and upon treatment of the lithio derivative with methyl chloroformate, 2-methoxycarbonyl-lV-benzylthieno[3,2-f>]pyrrole (51) was obtained (Scheme 10). The a-proton in the thiophene ring is more reactive towards metal-hydrogen exchange compared to the proton at C-5. 

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