Reactions of complex ligands part 106. Heterobimetallic fused arenes: Chromium-templated benzannulation of a ferrocene-type metal carbene

The heterobimetallic iron cyclopentadienyl(indenyl)carbene chromium complex 3 was synthesized from 5-bromoindene by via metalation with C5H5Fe(CO)2I, photodecarbonylation and chromium carbene functionalization of the π-bromoindenyl(cyclopentadienyl)iron intermediate 2. The chromium-templated benzannulation with 3-hexyne afforded syn- and anti-diastereomers of heterobimetallic hydroquinoid arene Cr(CO)3 complexes 4a and 4b which were characterized by X-ray, spectroscopic and electrochemical means.