Solid-Phase Total Synthesis of Dehydrotryptophan-Bearing Cyclic Peptides Tunicyclin B, Sclerotide A, CDA3a, and CDA4a using a Protected β-Hydroxytryptophan Building Block

A new approach to the synthesis of Z-dehydrotryptophan (ΔTrp) peptides is described. This uses Fmoc-β-HOTrp(Boc)(TBS)-OH as a building block, which readily prepared in high yield and incorporated into using solid-phase Fmoc chemistry. The tert-butyldimethylsilyl-protected indolic alcohol eliminated during global deprotection/resin cleavage give ΔTrp exclusively thermodynamically favored Z isomer. was applied tunicyclin B, sclerotide A, CDA3a, CDA4a.