Syntheses of IAA- and IPA-amino acid conjugates

Amino acid derivatives of IAA and IPA are prepared conveniently and efficiently by coupling of readily available 2a-b with diverse free amino acids 3a-g and (3c+3c') to give compounds 4a-j, (4c+4c') and (4h+4h') in 38-70% yields. Similarly, 2a-b afforded IAA and IPA peptide conjugates 6a-b in 32-40% yields. Complete retention of chirality was supported by NMR and HPLC analysis.