Organoruthenium(II) and (III) amidinates, (eta-(5)-C5Me5)Ru(eta-amidinate) and (eta(5)-C5Me5)RuCl(eta-amidinate), as unique redox catalysts for the intramolecular Kharasch reactions: Facile access to a pyrrolizidine alkaloid skeleton under mild conditions

A novel organoruthenium(III) amidinate, (eta(5)-C5Me5) RuCl( eta-(PrN)-Pr-i=C(Me) (NPr)-Pr-i) (2), has been prepared by oxidation of organoruthenium amidinate, (eta(5) -C5Me5)Ru(eta-(PrN)-Pr-i=C( Me)(NPr)-Pr-i) (1), by organic chlorides; both 1 and 2 are found to be good catalysts for atom-transfer cyclization of N-allyltrichloroacetamides which are useful for successful preparation of a pyrrolizidine alkaloid skeleton under mild conditions.