Total Synthesis of Tagetitoxin

The intriguing structure
of tagetitoxin (1), a long-standing
challenge in natural product synthesis, has been the subject of multiple
revisions and has been confirmed through total synthesis. The route
commences from a renewable furan starting material and features a
number of unusual transformations (such as rearrangements, bromocyclization,
and P­(V)-based phosphate installation) to arrive at the target in
15 steps. As the route was designed to enable access to both enantiomers,
the absolute configuration of the natural product could be assigned
using a bioassay on (+)-1 and (−)-1.