Total synthesis of the antiviral marine natural product (-)-hennoxazole A

[GRAPHICS] The marine natural product hennoxazole A was synthesized by a convergent ap proach. The diastereoselective Mukaiyama aldol reaction with beta -alkoxy a ldehyde was used to construct the tetrahydropyran segment, and the preparat ion of the nonconjugated triene moiety was accomplished via S(N)2 displacem ent of allylic bromide with vinyllithium and Takai's iodoolefination follow ed by palladium-catalyzed cross coupling with MeMgBr. The final steps invol ve an amide coupling using DEPC and oxazole synthesis via a oxidation/cyclo dehydration process.