Rhodium-Catalyzed Annulation of Vinylated Tyrosines with Internal Alkynes to Access Oxepine-Mounted Unnatural Tyrosines and Its Peptide Late Stage Functionalization
Synthesis of tyrosine derivatives for saframycin MX1 biosynthetic studies
摘要:
Saframycin MX1 and structural relatives are natural anticancer agents isolated from bacteria and marine invertebrates. For biosynthetic studies and to make a library of modified natural products, a series of tyrosine derivatives were synthesized in a concise manner. (C) 2004 Elsevier Ltd. All rights reserved.
Proton-coupled electrontransfer (PCET) was examined in a series of biomimetic, covalently linked Ru(II)(bpy)(3)-tyrosine complexes where the phenolic proton was H-bonded to an internal base (a benzimidazyl or pyridyl group). Photooxidation in laser flash/quench experiments generated the Ru(III) species, which triggered long-rangeelectrontransfer from the tyrosine group concerted with short-range