Synthesis of novel organometallic compounds containing eta(1)-carbon polycyclic ligands: Condensation of propargyl alcohol with the allenylidene ligand of [Ru(eta(5)-C5H5) (C = C = CPh2)(CO)(PPr3i)]BF4

The allenylidene complex [Ru(eta(5)-C5H5){C=CPh2}(CO)(PPr3i)]BF4 (1) reacts with propargyl alcohol to give the alpha,beta-unsaturated alkoxycarbene de rivative [Ru(eta(5)-C5H5){C(OCH2C = CH)CH=CPh2}(Co)(PPr3i)]BF4 (2) The stru cture of 2 was determined by an X-ray investigation, revealing a Ru-C dista nce of 1.965(4) Angstrom. Treatment of 2 with 1 equiv of Na-2-CO3 affords [ Ru(eta(5)-C5H5){9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanylidene)(CO)(PPr3 i)]BF4 (3), which reacts with NaBH4 to give Ru(eta(5)-C5H5)(CH2(1-phenyl-3- hydroxymethyl-2-naphthyl)}-(CO)(PPr3i) (4). The structure of 3 was determin ed by an X-ray diffraction analysis, revealing a Ru-C bond length of 2.004( 2) Angstrom. Treatment of 2 with 3 equiv of NaOCH3 leads to a mixture of co mpounds containing the racemic form (Ru-R,C-R;Ru-s,C-s)-Ru(eta(5)-C5H5)(9-p henyl-1,3-dihydronaphtho[2,3-c]-1-furanyl)(CO)(PPr3i)(5) as the main compon ent. This racemic form was obtained as a pure solid by passing the crude pr oducts 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, t he investigation reveals a Ru-C distance of 2.203(3) Angstrom. When the cru de products were passed through an Al2O3 column using a pentane/diethyl eth er (5:1) mixture, the epimerization of 5 into (Ru-R,C-s;Ru-s,C-R)-Ru(eta(5) -C5H5)(9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanyl)(CO)(PPr3i) (6) was obs erved. When the above-mentioned chromatography is carried out using an incr easing polarity mixture of toluene/diethyl ether (from 10:1 to 1:10) as elu ent, the transformation of 5 into its isomer Ru(eta(5)-C5H5)(CH2(1-phenyl-3 -carboxa-2-naphthyl))(CO)(PPr3i) (7) occurs. The complex Ru(eta(5)-C5H5)(9- phenyl-3,3a-dihydronaphtho[2,3-c]-1-furanyl)(CO)(PPr3i) (8) was also synthe sized, by passing 2 through an Al2O3 column using a tetrahydrofuran/dichlor omethane (5:1) mixture as eluent.