Synthesis of heterocyclic ligands by diheterocyclization at the rhenium(I) allenylidene [(triphos)(CO)(2)Re{C=C=CPh2}](OSO2CF3). 1. Reactivity with dipolar N,N-heterocycles

1,2,3-Diheterocyclizations at the allenylidene ligand in the complex [(triphos)(CO)2Re{CdCdCPh2}]- OTf (1; triphos ) MeC(CH2PPh2)3, OTf ) OSO2CF3) readily occur upon reacting 1 with N,N-heterocycles such as 1H-benzotriazole, 2-aminopyridine, and 2-aminothiazole. The reaction of 1 with 1H-benzotriazole leads to [(triphos)(CO)2Re{CdC(H)C(Ph)}]N(C6H4)NdN}]OTf (4). Deprotonation of 4 with sodium methoxide in tetrahydrofuran at room temperature yields the alkynyl derivative [(triphos)(CO)2Re{Ct CC(Ph)2(NC6H4NdN)}] (5) via ring opening of the triazaindenyl moiety in 4. Reaction of 1 with 2-aminopyridine or 2-aminothiazole in CH2Cl2 leads to the heterobicyclic compounds [(triphos)(CO)2Re- {CdC(H)C(Ph)2N(H)C(CH)4N}]OTf (6) and [(triphos)(CO)2Re{CdC(H)C(Ph)2N(H)CS(CH)2N}]OTf (8), respectively. Both complexes undergo regioselective deprotonation at the N-H heterocycle group by treatment with sodium methoxide in THF, giving the neutral species [(triphos)(CO)2Re{CdC(H)C- (Ph)2NC(CH)4N}] (7) and [(triphos)(CO)2Re{CdC(H)C(Ph)2NCS(CH)2N}] (9), respectively. The X-ray structures of the new organorhenium species 4 and 7-9 have been determined, which have confirmed that the addition of the NH bond of the N,N-heterocycle occurs always across the Cbeta-Cgamm double bond of the allenylidene chain.