C-N and C-C coupling reactions:: Preparation of new N-heterocyclic ruthenium derivatives

Three novel types of complexes containing heterocyclic ligands are prepared by condensation of the allenylidene ligand of [Ru(eta(5)-C5H5)(=C=C=CPh2)(CO)((PPr3)-Pr-i)]BF4 (1) With propargylamines. Complex 1 reacts with propargylamine to give initially [Ru(eta(5)-C5H5)-{C(CH=CPh2)=NHCH(2)Cequivalent toCH}(CO)((PPr3)-Pr-i)]BF4 (2). Treatment of 2 with KOH in methanol affords the bicyclic derivative Ru(eta(5)-C5H5){4-methylidene-6,6-diphenyl-2-azabicyclo[3.1.0]-hex-2-en-1-yl}(CO)((PPr3)-Pr-i) (3). The formation of 3 takes place via the intermediate Ru(eta(5)-C5H5){C(CH=CPh2)=NCH(2)Cequivalent toCH}(CO)((PPr3)-Pr-i) (4), which is isolated when the deprotonation of 2 is carried out in tetrahydrofuran as solvent. In contrast to propargylamine, the addition of 1,1-diethylpropargylamine to 1 leads to the dihydropyridiniumyl derivative [Ru(eta(5)-C5H5)-{2,2-diethyl-5-diphenylidene-2,5-dihydropyridinium-6-yl)(CO)((PPr3)-Pr-i)]BF4 (5) in a one-pot synthesis. Complex 1 also reacts with N-methylpropargylamine. The reaction affords [Ru-(eta(5)-C5H5){C(CH=CPh2)=N(CH3)CH(2)Cequivalent toCH}(CO)((PPr3)-Pr-i)]BF4 (6). Treatment of 6 with sodium methoxide, at -78 degreesC, gives a 1:1 mixture of the dihydronaphthopyrrolyl diastereomers (RRuSC,SRuRC)-[Ru(eta(5)-C5H5){9-phenyl-4,4a-dihydronaphtho[2,3-c]-1-pyrrolyl})(CO)((PPr3)-Pr-i) (7a) and (RRuRC,SRuSC)-[Ru(eta(5)-C5H5){9-phenyl-4,4a-dihydronaphtho[2,3-c]-1-pyrrolyl})(CO)((PPr3)-Pr-i) (7b). Complexes 3 and 5 and the enantiomeric mixture 7a have been characterized by X-ray diffraction analysis.