SYNTHESIS, STEREOCHEMISTRY AND DECOMPLEXATION OF (ETA-ARENE)(ETA-CYCLOPENTADIENYL) IRON(II) HEXAFLUOROPHOSPHATE COMPLEXES CONTAINING AMINO-ACID SIDE-CHAINS - A ROUTE TO N-ARYLAMINO ACIDS

[(eta-Substituted arene)(eta-cyclopentadienyl)Fe][PF6] complexes with amino acid side chains on the arene ring have been prepared by reactio n of [(eta-haloarene)(eta-cyclopentadienyl)Fe][PF6] complexes with ami no acids and amino acid eaters under various conditions. Evidence is p resented from H-1-and C-13-NMR spectroscopy for the existence of confo rmational isomers resulting from restricted rotation about the arene-n itrogen bond. Where a chlorine substituent is also present in the comp lexed arene, diastereoisomers can be separated by column chromatograph y. Decomplexation of the complexes is reported in strongly basic media or using 1,8-phenanthroline in light-catalysed reactions offering a n ew route to N-arylamino acids. (C) 1997 Elsevier Science S.A.