Li-Barbier Reactions with n-Butyllithium

A quite different version of the Li-Barbier reaction, which was recently published [38], has already been referred to on p. 86 n-Butyllithium was used to generate the intermediate lithium compound from iV-(2-iodobenzyl) phenacyla-mine, achieving the first ever reported intramolecular Barbier reaction, with an aryl halide. As was the case with the iodonitrile (p. 86 of this Section), the metal-halogen exchange reaction of the n-butyllithium proved to be much faster than the carbonyl addition reaction. 

Eleven different iodides were cyclized in this manner with yields which varied from 50 to 86%. 

Only in a few instances was the reduced product, resulting from hydrolysis of uncyclized aromatic lithium compound, obtained in relatively high yield 

Reactions with bromides were less successful. 

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