[structure:see text] The marinenaturalproduct hennoxazole A was synthesized by a convergent approach. The diastereoselective Mukaiyama aldol reaction with beta-alkoxy aldehyde was used to construct the tetrahydropyran segment, and the preparation of the nonconjugated triene moiety was accomplished via S(N)2 displacement of allylic bromide with vinyllithium and Takai's iodoolefination followed by
The antiviral marine natural product (-)-hennoxazole A was efficiently synthesized by a convergent approach. The stereoselective synthesis of the functionalized tetrahydropyran fragment was accomplished by the Mukaiyama aldol reaction, chelation-controlled 1,3-syn reduction, Wacker oxidation, and acid catalyzed intramolecular ketalization. The nonconjugated triene fragment was synthesized by S(N)2 displacement of an allylic bromide with vinyllithium and the CrCl2-mediated iodoolefination followed by palladium-catalyzed cross coupling with MeMgBr. The final steps include the fragment coupling using DEPC and oxazole synthesis via an oxidation/cyclodehydration process. (C) 2001 Elsevier Science Ltd. All rights reserved.