The Structure Elucidation of Haprolid

Abstract

The assignment of two stereocenters of the natural product haprolid through the application of a profile hidden Markov model (HMM) and its confirmation through total synthesis of the natural product and of two of its diastereomers are reported. The structure elucidation of this polyketide-peptide hybrid natural product is a telling showcase of how difficult it can be to determine the absolute configuration of isolated stereocenters and the benefits of a gene cluster analysis for structure determination. The key steps of the synthesis are a selective epoxidation of a terminal olefin and the stereodivergent macrolactonization strategy. Furthermore, the biological evaluation of all products showed that all diastereomers are potent inhibitors of hepatocellular carcinoma cell lines.