Lithium Diisopropylamide-Mediated Carbolithiation Reactions of Vinylidenecyclopropanes and Further Transformations of the Adducts

Highly stereo- and regioselective carbolithiation reactions of vinylidenecyclopropanes 1 were realized by treatment with lithium diisopropylamide (LDA) in THF and by quenching with various electrophiles such as aryl or aliphatic aldehydes, ketones, enones or propargyl bromide. Transformation of these adducts such as vinylcyclopropenes and allenols was also performed in the presence of Lewis acid or Bronsted acid to provide the fused and conjugated aromatic products in good to high yields under mild conditions.