Metal complexes with biologically important ligands.: 122.: Carbonyl rhenium and palladium enolate complexes from Schiff bases of glycine and peptide esters.: C-C coupling and [2+3]-cycloadditions

Deprotonation of carbonyl rhenium and palladium compounds of N-(diphenylmethylene) Schiff bases from glycine and peptide esters provides the corresponding enolate complexes in good yields which have proven to be useful precursors for the synthesis of organometallic alpha-amino acid and peptide derivatives. With pi-coordinated hydrocarbons as electrophiles ([(C2H4)Re(CO)(5)](+) BF4- [(C6H7)Fe(CO)(3)](+) BF4-) the bimetallic complexes 13-18 are obtained under C-C coupling. [2 + 3] cycloaddition reactions of the palladium enolates with N-phenyl- and N-methyl-1,2,4-triazoline-3,5-dione yield the peptide derivatives 19-21.