Carboannulation of o-Bromobenzyl Zinc Bromide with Alkenes and Alkynes

Significance

Indene and indane scaffolds are present in many biologically active compounds. Indene is also an important motif in modern catalysts for selective olefin polymerization. This reaction gives an operationally simple one-step method for the regioselective preparation of indenes and indanes from readily available starting materials. The use of TMS alkynes, followed by the removal of the TMS group by CF₃CO₂H provides a general method for the preparation of both 1- and 2-substituted indenes from the same alkyne.