REACTIONS OF COMPLEX LIGANDS .52. 6-MEMBERED AMINO CARBENE CHELATE COMPLEXES - SYNTHESIS, ALKYNE-CARBENE COUPLING AND CARBENE ANELLATION

The photoinduced decarbonylation of pentacarbonyl[(2-N,N-dimethylamino)anilino(phenyl resp. 4-methylphenyl)carbene]chromium (1,2) leads to the formation of the tetracarbonyl carbene(C,N) complexes 3 and 4 which contain a six-membered chelate ring. These complexes react with internal alkynes to give either the tetracarbonyl(iminoindane-N,N) chelates 5 and 6 or the tricarbonyl(iminoindane) and -(aminoindene) complexes 7-10, respectively, depending on the solvent used. An X-ray diffraction study of 6 reveals a relative trans stereochemistry of the former alkyne substituents in the indane skeleton, an envelope conformation of the five-membered chelate ring and a Z-configuration within the imine ligand. Cleaving off the metal, under atmospheric pressure of CO, affords a mixture of iminoindane 12 and aminoindene 13. Unlike internal alkynes, terminal alkynes react with 3 to give the tetracarbonyl[azabutadiene(N,N)] chelate complexes 14 and 15.