Syntheses of Nonracemic Ortho-Mercurated and Ortho-Ruthenated Complexes of 2-[Tricarbonyl(η⁶-phenyl)chromium]pyridine

Abstract

The reaction of racemic orthomercurated (η 6 -arene)tricarbonylchromium complexes with bis[(η 6 -cymene)ruthenium(II)dichloride] affords the corresponding dinuclear (Cr,Ru) products with moderate yields, which have been satisfactorily characterized by X-ray diffraction analysis. The synthesis of nonracemic orthomercurated (η 6 -arene)tricarbonylchromium complexes has been attempted starting from enantio-enriched homo- and heteroleptic Pd(II) bischelated complexes. Both enantiomers of ortho-mercurated 2-[tricarbonyl(η 6 -phenyl)chromium]pyridine have been synthesized by reaction of a heteroleptic Pd(II) bischelated with HgCl 2 . The two mercury(II) complexes were also submitted to a transmetalation reaction with bis[(η 6 -cymene)ruthenium(II)dichloride] and yielded the corresponding nonracemic (Cr, Ru) products, with enantiomeric excesses ranging from 82 to 89% as suggested by 1 H NMR analyses in the presence of BINPHAT anion.