Stepwise conversion of a linear peptide covalently attached to a cellulose membrane into a cyclic decapeptide that incorporates four antiparallel helical appendages. The fragment T4-Ah was synthesized on a resin loaded with a peptide amide linker. Synthesis steps: (i) Pd(0) in DCM, TBTU/DIEA in DMF; (ii) hydrazine in DMF; (iii) solid-phase synthesis; (iv) 19/1 TFA/DTT, HPLC; (v) phosphate buffer/acetonitrile (2/1), pH 8; (vi) DTT, pH 7.8, 10 equiv. of helix Bv, pH ≈ 8; (vii) Hg(OAc)2, pH 4.0, 10 equiv of helix Ck, pH ≈ 8, P(Ph)3 in n-propanol/buffer, pH 7.8. Reproduced with permission from ref 917. Copyright 2001 American Chemical Society.