Scheme 1. Sonogashira cross-coupling modification of natural product analogues. (A) Labelling of iodophenyl derivatives with fluorescent tags.9 (B) Cross-coupling of iodinated pyrimidine nucleoside.7a (C) Sonogashira cross-coupling of unprotected bromotryptophans. (D) Sonogashira cross-coupling of 7-bromotryptophan in a tripeptide system. (E) New to nature bromo-cystargamide.
