CNR and CO Insertion Reactions of 2,6-Xylyl Isocyanide with <i>p</i>-Chlorobenzylpentacarbonylmanganese

Stirring a solution of (CO)5MnCH2C6H4-p-Cl, 1, with 2 equiv of 2,6-xylyl isocyanide in toluene in the presence of a catalytic amount of PdO produced isocyanide insertion products including the bis(iminoacyl) 3, and the first octahedrally based tris(iminoacyl) 6. The same reaction in THF afforded the carbonyl insertion product (CO)3(xylyl-NC)2MnC(O)CH2C6H4-p-Cl, 9. Reaction of 1 with 1 equiv of xylyl isocyanide in THF without PdO produced the expected acyl (CO)4(CN-xylyl)MnC(O)CH2C6H4-p-Cl, 11, along with a minor quantity of 3. Exposure of the reaction mixture to CO2 afforded the unique dimanganese species 12, in which the manganese centers are linked through a carbamato bridge. X-ray structures of 3, 6, and 12 are reported.