Iron-catalyzed aryl- and alkenyllithiation of alkynes and its application to benzosilole synthesis

Phenyl- and vinyllithiums having an alkyl substituent at their ortho- and cis-position, respectively, readily added to alkynes in the presence of 5 mol% of Fe(acac)₃. The reaction of o-(trimethylsilyl)phenyllithium with alkynes gave benzosiloles through an addition–cyclization sequence.