Stereochemistry of Metallocenes, 44. Syntheses and Configurations of Tricarbonylchromium Complexes of Diphenic Acid and Its Derivatives (Biphenyl Tricarbonylchromium Complexes, 3)

Article abstract of DOI:10.1007/BF00938733

Mono and bis tricarbonylchromium complexes of diphenic acid and its monomethylester (3, 4, 15, 16) were prepared by treating the corresponding methyl and trimethylsilylesters (e.g. 12) with Cr(CO)6 and subsequent hydrolysis of the complexes 1, 2, 13, and 14.Diborane reduction of the carboxylic acids gave hydroxymethyl derivatives, amongst which the diol 8a is a key substance for configurational analyses by 1H-nmr and ir spectroscopy.In this context monosubstituted biphenyl complexes (9-11) were prepared as reference substances.Complexation of the lactone 23 of 2'-hydroxymethyl biphenyl-2-carboxylic acid afforded (besides two isomeric monocomplexes) mainly the trans-biscomplex 26b, a key intermediate for ring opening and cyclization reactions.The stereochemical possibilities of the biscomplexes are discussed.The "racemate" configuration is preliminarily assigned to diphenic acid bistricarbonylchromium and its derivatives. - Keywords: Benchrotrenes; Hydrogen bridges, intramolecular; Lactone of 2'-hydroxymethyl-biphenyl-2-carboxylic acid, mono and bis tricarbonylchromium