Late-stage macrolactonisation enabled by tandem acyl transfers followed by desulphurisation.

Intramolecular -acylation of a thiol-installed threonine with a thioester unit, followed by S-O acyl transfer and subsequent desulphurisation, allows the synthesis of lactone peptides. A protocol has been developed enabling the cyclisation of a linear peptide, a reaction which has not been achieved by conventional methods.