Heterobimetallic Dibenzoindenyl (Cr(CO)3–Re(CO)3) Complexes via Chromium-Templated [3 + 2 + 1]Benzannulation: Synthesis and Molecular Structures

Heterobimetallic (di)benzoindenyl Re–Cr complexes have been prepared by a sequence starting from (8-bromobenzo[e]-indenyl)potassium. Reaction with pentacarbonylrhenium bromide affords tricarbonylrhenium complex 2, which has been modified to rhenium–chromium carbene complex 3. Its chromium-templated [3 + 2 + 1]benzannulation afforded the anti(Cr(CO)3–Re(CO)3) dibenzoindenyl complex 4 as the major product along with the syn diastereoisomer 5. The molecular structures of all heterobimetallic complexes were established by X-ray analyses.