One-pot ligation strategy for atypical ubiquitin chains synthesis by using the trifluoroacetamidomethyl-protected isopeptide-linked Ub (Tfacm-isoUb) unit

•A new one-pot ligation approach was developed for the synthesis of atypical Ub chains based on the Tfacm-isoUb building block.•The key intermidate Tfacm-isoUb building block can be readily prepared by Fmoc SPPS.•The practicality and efficiency of the new one-pot method is demonstrated by the successful preparation of K11-linked di-Ub.