A convergent synthesis of poststatin: Application of the acyl cyanophosphorane coupling procedure in the formation of a peptidic α-keto amide

A convergent synthesis of the pentapeptide poststatin has been developed. The key step involves oxidative cleavage of an acyl cyanophosphorane. The resulting α,β-diketo nitrile is then coupled to the free amine of a C-terminal-dipeptidyl component to generate the protected natural product. Deprotection by hydrogenolysis furnishes poststatin.