Iron(III)/NaBH4-Mediated Additions to Unactivated Alkenes: Synthesis of Novel 20′-Vinblastine Analogues

An Fe(III)/NaBH4-mediated reaction for the functionalization of unactivated alkenes is described defining the alkene substrate scope, establishing the exclusive Markovnikov addition, exploring a range of free radical traps, examining the Fe(III) salt and initiating hydride source, introducing H2O–cosolvent mixtures, and exploring catalytic variants. Its use led to the preparation of a novel, potent, and previously inaccessible C20′-vinblastine analogue.