Selective reactivity of diamino Fischer-type carbene complexes towards 2,6-disubstituted and 2,4,6-trisubstituted pyrylium salts and 2,4,6-trichloro-1,3,5-triazine

The synthesis of new amino Fischer-type carbene complexes 2a–d with amino-containing side chain is presented. The reaction of these complexes with 2,4,6-triarylpyrylium salts gave the corresponding pyridinium salt 4a, 4c–e as expected from the initial attack of the free amino group onto the pyrylium α-carbon. When using the 2,6-diphenylpyrylium salt, a γ-addition of the amino group occurred, leading – after an hydrogen migration and a ring opening step – to the new organometallic unsaturated aminoketone 5. Finally, the reactivity of the diaminocarbene 2b with 2,4,6-trichloro-1,3,5-triazine has been investigated. The new triazine 6 bearing a ferrocenylaminocarbene group was isolated.

The reaction of alkoxy Fischer-type carbene complexes with diamines gave amino carbenes with pendent NH2. The free amino group of these complexes which could act as markers for biomolecules reacted with pyrylium salts to give pyridinium salts or a new 1,5-organometallic aminoketone. In addition, reaction with 2,4,6-trichloro-1,3,5-triazine gave a monosubstituted product.Figure optionsDownload as PowerPoint slide