RING-METHYL ACTIVATION IN PENTAMETHYLCYCLOPENTADIENYL COMPLEXES - 8 -INTRODUCTION OF ORGANIC FUNCTIONALITIES AT SUBSTITUTED TETRAMETHYLCYCLOPENTADIENYL COMPLEXES OF RUTHENIUM(II)

A series of complexes derived from nucleophilic attack at the CH2Cl of [(eta(5)-C5Me4CH2Cl)Ru(CO)(2)Cl], 1, by a wide variety of organic rea gents are described. Most reactions proceed in good yield and do not a ppear to affect the Ru(CO)(2)Cl group, even though they are performed under quite stringent (oxidizing, acidic, or hydrolytic) conditions. H ydrolysis of 1 in the presence of collidine gives the alcohol complex, [(C5Me4CH2OH)Ru(CO)(2)Cl], 2, which is oxidized (Me2SO, oxalyl chlori de) to [(C5Me4CHO)Ru(CO)(2)Cl], 4a, and which can be further oxidized (KMnO4) to [(C5Me4CO2H)Ru(CO)(2)Cl], 10. The alcohol complex 2 forms e sters [(C5Me4CH2O2CR)Ru(CO)(2)Cl], 3 (R = Me, CH2=CH, 2-furyl, and 2-t hienyl), on reaction with RCOCl/Et3N. The aldehyde 4a is a very versat ile starting material: It forms acetals such as [(C5Me4CH(OCH2)(2))Ru( CO)(2)Cl], 5a, with ethylene glycol. It reacts with phenylhydrazine an d p-toluidine in the presence of acid to give [(C5Me4CH=NNHPh)Ru(CO)(2 )Cl], 6, and [(C5Me4CH=N-p-To)Ru(CO)(2)Cl], 7. It also reacts with car bon nucleophiles such as PhMgBr to give [(C5Me4CH(OH)Ph)Ru(CO)(2)Cl], 8a, with lithium enolates to give [(C5Me4CH(OH)R)Ru(CO)(2)Cl], 8b-d (R = 2-oxocyclohexyl, MeCOCH2, and PhCOCH2), and with Wittig reagents to give [(C5Me4CH=CHR)Ru(CO)(2)Cl], 9 (R = EtCO2, Ph, MeCO, and PhCO). T he carboxylic acid 10 forms the acid chloride [(C5Me4COCl)Ru(CO)(2)Cl] , which reacts with diisopropylamine to give the amide [(C5Me4CON(i-Pr )(2))Ru(CO)(2)Cl], 12. The structures of complexes [(C5Me4CH(oH)Ph)Ru( CO)(2)Cl], 8a, [(C5Me4CH(OH)CH2COPh)Ru(CO)(2)Cl], 8d, and [(E-C5Me4CH= CHPh)Ru(CO)(2)Cl], 9b, have been confirmed by X-ray determinations.