Ketomethylene isosteric amide bond replacements via the zinc -mediated chain extension of N -protected amino acids

A methodology for the chain extension of N-protected amino acid beta-keto esters to gamma-keto esters utilizing a zinc carbenoid was developed. The reaction was used on amino acids containing various protective groups and a variety of side chain functionality. This method was used in the incorporation of ketomethylene isosteric amino acid replacements within amino acid sequences. The usefulness of the method on molecules supported by a solid phase was explored