Organometallic dipeptide ester complexes of the general formula [ (L)M(CI)(K'-NHZCH~CONCH,CO,R)] (1: L = Cp*, M = Rh, 2: L = Cp*, M = Ir, 3: L = q6-C6Me6, M = Ru) react smoothly with various a-L-amino acid esters in the presence of NEt, to yield the tripeptide ester complexes [(L)M(CI)(K'-
NH,CHR'CONCH,CONHCH,CO,R)](5-7). In the same fashion chloro K 'tetrapeptide ester complexes 10 and 11 are obtained either from tripeptide ester com-plexes or by subsequent addition of two equivalents of amino acid ester to a dipeptide ester complex. When the strong base NaOMe is used in the reaction of the diglycine ester compounds with amino ~ 1520 - . 0-69451 Weinheim. 1996 0947-6S39/96/0212-IS20 d IS.O0+.2S/O Chem. Eur. J. 1996, 2. No. I2 Oligopeptide Synthesis 151 8 -1 526 Chem. Eur. 1. 1996, 2, No. 12 Q VCH Verlagsgesellschaff mhH. D-69451 Weinheim. 1996 0947-6539/96/0212-l521 S 15.00+.25/0 63 VCH VerlaPsPesellscha/r mbH, 0.69451 Weinheim, 19% 09474539/96/0212-1522 d I5.OOi.25lO