Synthesis of 2-Pyrrolyl Complexes of Ruthenium and Osmium via Hydrolysis of a Chloro(pyrrolyl)carbene Ligand or via Transmetalation Reactions Using (2-Pyrrolyl)mercuric Chloride
摘要:
The chloro(2-pyrrolyl)carbene complex Ru(=C[Cl]-2-C4H3NH)Cl2(CO)(Pph3)2 (1) undergoes hydrolysis and rearrangement to give the sigma-bound 2-pyrrolyl complex Ru(2-C4H3NH)Cl(CO)2(Pph3)2(2). Compound 2, and the osmium analogue Os(2-C4H3NH)Cl-(CO)2(Pph3)2 (4), can be prepared by reaction of (2-pyrrolyl)mercuric chloride (3) with the low-oxidation-state compounds M(CO)2(Pph3)3 (M = Ru, Os), respectively. Key steps in the synthesis of compound 3 involve protection of the pyrrolic nitrogen atom with a lithiocarboxylate function followed by selective lithiation and then mercuration in the ring 2-position.