1-(4,4-Dimethyl-2,6-dioxocyclohexylidene)-3-methylbutyl (ivDde), an amino protecting group cleavad by 2% hydrazine hydrate in DMF. ivDde is more stable towards the repetitive piperidine treatments during Fmoc-SPPS than Dde. Nω-ivDde can be selectively removed from Dap, Dab Orn, or Lys allowing post-synthetic on-resin modification of the Nω-amino group.