Further studies on enantioselective synthesis of (+)-anatoxin-a using enyne metathesis: unexpected inversion of chirality via a skeletal rearrangement of 9-azabicyclo[4.2.1]nonene derivative

The formal total synthesis of (+)-anatoxin-a was accomplished using enyne metathesis as a key step. It is very interesting that (+)-anatoxin-a was synthesized from (S)-pyroglutamic acid via an unusual inversion of chirality, which is rationalized in terms of a skeletal rearrangement of 9-azabicyclo[4.2.1]nonene derivative at the stage of oxymercuration of the diene.