Synthesis of the Key Intermediate of SM-406 (Xevinapant) and Its Analogues

Efficient methods for the synthesis of three dipeptide mimetics with diazabicycloalkanone amino acid scaffolds were developed. Among them, compound 3, which contains a 1,5-diazabicyclo[6,3,0]dodecanone amino acid core structure, was used as the key intermediate of a clinical staged IAP inhibitor SM-406 (Xevinapant). Compared with the reported methods for the synthesis of compound 3 and its derivatives, our method is more efficient and more suitable for large scale preparation.