Cyclisation of α,β,γ,ψ-unsaturated dioic acid esters via tandem conjugate additions by using lithium N-benzyltrimethylsilylamide (LSA) as a nitrogen nucleophile and its application to a total synthesis of (±)-dihydronepetalactone and (±)-isodihydronepetalactone

A stereoselective total synthesis of (±)-dihydronepetalactone and (±)-isodihydronepetalactone has been accomplished by utilising a novel cyclisation procedure; a reaction of octadiene-2,6-dioic acid esters with lithium N-benzyltrimethylsilylamide (LSA) induces 5-exo-Trig ring-closure via tandem conjugate additions.