Synthesis of novel organometallic compounds containing η1-Carbon polycyclic ligands: Condensation of propargyl alcohol with the allenylidene ligand of [Ru(η5-C5H5)(C=C=CPh2)(CO)(PPri3)]BF4

The allenylidene complex [Ru(η5-C5H5){C=C=CPh 2}(CO)(PPri 3)]BF4 (1) reacts with propargyl alcohol to give the α,β-unsaturated alkoxycarbene derivative [Ru(η5-C5H5){C(OCH2C≡ CH)CH=CPh2}(CO)(PPri 3)]BF4 (2). The structure of 2 was determined by an X-ray investigation, revealing a Ru-C distance of 1.965(4) Å. Treatment of 2 with 1 equiv of Na2-CO3 affords [Ru(η5-C5H 5){9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanylidene}(CO)(PPr i 3)]BF4 (3), which reacts with NaBH4 to give Ru(η5-C5H5){CH 2(1-phenyl-3-hydroxymethyl-2-naphthyl)}-(CO)(PPri 3) (4). The structure of 3 was determined by an X-ray diffraction analysis, revealing a Ru-C bond length of 2.004(2) Å. Treatment of 2 with 3 equiv of NaOCH3 leads to a mixture of compounds containing the racemic form (RuR,CR;RuS,CS)-Ru(η 5-C5H 5){9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanyl}(CO)(PPr i 3) (5) as the main component. This racemic form was obtained as a pure solid by passing the crude products through an Al2O3 column using diethyl ether as eluent. The structure of 5 was also determined by an X-ray diffraction analysis. In this case, the investigation reveals a Ru-C distance of 2.203(3) Å. When the crude products were passed through an Al2O3 column using a pentane/diethyl ether (5:1) mixture, the epimerization of 5 into (RuR,CS;RuS,CR)-Ru(η 5-C5H 5){9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanyl}(CO)(PPr i 3) (6) was observed. When the above-mentioned chromatography is carried out using an increasing polarity mixture of toluene/diethyl ether (from 10:1 to 1:10) as eluent, the transformation of 5 into its isomer Ru(η5-C5H5){CH 2(1-phenyl-3-carboxa-2-naphthyl)}(CO)(PPri 3) (7) occurs. The complex Ru(η5-C5H 5){9-phenyl-3,3a-dihydronaphtho[2,3-c]-1-furanyl}(CO)(PPr i 3) (8) was also synthesized, by passing 2 through an Al2O3 column using a tetrahydrofuran/dichloromethane (5:1) mixture as eluent.We acknowledge financial support from the DGES of Spain (Project PB98-1591).Peer Reviewe