A study on the impact of catharanthine C10 and C12 indole substituents on the biomimetic Fe (III)-mediated coupling with vindoline led to the discovery and characterization of two new and substantially more potent derivatives, 10′-fluorovinblastine and 10′-fluorovincristine. In addition to defining a pronounced and unanticipated substituent effect on the biomimetic coupling, fluorine substitution at C10′, which minimally alters the natural products, was ...
[Magnus, Philip; Mendoza, Jose S.; Stamford, Andrew; Ladlow, Mark; Willis, Paul Journal of the American Chemical Society, 1992 , vol. 114, # 26 p. 10232 - 10245]