Ruthenacycles with stereogenic metal centers:: Synthesis and characterization of cycloruthenated (R)C-(+)-N,N-dimethyl-α-(2-naphthyl) ethylamine (TMNA);: crystal structures of [( η6-C6H5Me)Ru(TMNA)(X)], (X = Cl, Br, I)

The transmetallation reaction of enantiomerically pure (R-C)-{HgCl[C10H6CH(Me)NMe2]} with the [(eta(6)-arene)RuCl2](2) dimer, where eta(6)-arene=C6H5-Me (toluene), in CH3CN at ambient temperature forms a mixture of two diastereomeric ruthenacycles [(S-Ru, R-C) - a, major, and (R-Ru, R-C) - a', minor] of the type {(eta(6)-arene)Ru[C10H6CH(Me)NMe2](Cl)} (1a,a') in good chemical and optical yields. The diastereoselectivity of chloride substitution in 1a,a' by bromide and iodide has been determined by H-1 and C-13{H-1} NMR spectroscopy and single-crystal X-ray crystallography. The diastereoselectivity of this type of transmetallation reaction varies as a function of both the electronic nature of the (eta(6)-arene) ligand attached to the ruthenium center and the steric nature of the chiral arylamine (de is the diastereomeric excess): [(eta(6)-benzene)Ru(TMNA)Cl] (TMNA=[C10H6CH(Me)NMe2]), 8a,a', (92% de)>[(eta(6)-benzene)Ru(TMBA)Cl], (TMBA=[C6H4CH(Me)NMe2]), 5a,a', (90.4% de)>[(eta(6)-toluene)Ru(TMNA)Cl], 1a,a', (87.5% de)>[(eta(6)-toluene)Ru(TMBA)Cl], 4a,a', (86.7% de). The diastereoselectivity of the substitution reactions generally increases with increasing steric bulk of the incoming ligand and proceeds with predominant retention of configuration at ruthenium. (C) 1999 Elsevier Science Ltd. All rights reserved.