Chiral Arene Ruthenium Complexes. 6. Diastereoselective Formation of Chiral-At-Metal P-Tethered Arene Ruthenium(II) Complexes

Abstract

The easily accessible (R)-3-phenylbutanol (1) can be transformed into the novel enantiopure ligand diphenyl((R)-3-phenylbutyl)phosphane (3). 3 splits the complex dimer [{RuCl 2 (η 6 -C 6 H 5 CO 2 Me)} 2 ] (6) by adding as a σ-ligand to form mononuclear [RuCl 2 (η 6 -C 6 H 5 COOMe)-((R)-η 1 -PPh 2 (CH 2 ) 2 CH(CH 3 )Ph)] ( 7). An intramolecular arene ligand displacement reaction leads to [RuCl 2 ((R)-η 1 -PPh 2 (CH 2 ) 2 CH(CH 3 )-η 6 -C 6 H 5 )] ( 8) with a tethered side chain of the arene ligand. Nucleophilic substitution of a chloride ligand by primary or secondary amines with the assistance of NaBF 4 gives access to the diastereomeric complex salts [RuCl(amine)-((R)-η 1 -PPh 2 (CH 2 ) 2 CH(CH 3 )-η 6 -C 6 H 5 )]BF 4 . Good diastereoselectivities were obtained for aniline, piperidine, benzylamine, and butylamine complex salts 9-12 (de ) 82-90%). The absolute structures of 8-10 have been determined by X-ray structure analysis. S Ru ,R C configurations were found for the major diastereomers of aniline and piperidine complex salts 9 and 10. Not only the side chain stereogenic center but also the metal configuration of the cation of salt 9 is stable for longer periods at low and at elevated temperatures in different solutions.

Syntheses and characterization of [(η6-C6Me6)Ru(μ-N3)(X)]2 (X=N3 and Cl) complexes and their reactions towards mono- and bidentate ligands

“…The two Ru-N distances (2.105(2) and 2.145(2) Å ) are slightly different, as found in related structures with phosphine complexes (2.177(2) Å ) [24]. The average Ru-C(arene) distance is 2.242 Å .…”

Water‐Soluble Arene Ruthenium Complexes Containing a trans‐1,2‐Diaminocyclohexane Ligand as Enantioselective Transfer Hydrogenation Catalysts in Aqueous Solution

“…The starting dimer [(arene)RuCl 2 ] 2 [23,24] and the monotosylated diaminocyclohexane (TsHNʝNH 2 ) [20] were prepared according to the published methods. All other reagents were commercially available and were used without further purification.…”

The Stereospecific Ligand Exchange at a Pseudo‐Benzylic T‐4 Iridium Centre in Planar‐Chiral Cycloiridium (η6‐Arene)tricarbonylchromium Complexes

“…Keywords: chirality · metallacycles · organometallic compounds · stereoisomerization · stereoselectivity strained system. [19,20] This principle has been evaluated in many ways in attempts to constrain the configuration of the metal centre at pseudo-tetrahedral transition-metal centres of half-sandwich metallocenes within a limited number of configurations. [21][22][23][24] Complementary effects can be introduced to increase the stereoselectivity such as an overall molecular electrostatic unbalance around the metal centre subjected to ligand exchange.…”