Synthetic studies on dysiherbaine

Abstract

For the synthesis of dysiherbaine 1, the bicyclic oxazolidinone 40 has been synthesized starting from mannitol. cis,cis-Diene 131 could be accessed via palladium-catalyzed cross-coupling reaction of vinyl iodide 106 and terminal acetylene 90 under Sonogashira conditions. 131 was cyclized stereoselectively by intramolecular mercuriocyclization to give cis-dihydropyran 138b. N-Methyl- oxazolidinone 130 was achieved via iodocyclization of imidates. 130 was cyclized by an intramolecular $S_N2$ reaction regiospecifically to give the desired tetrahydrofuran rather than tetrahydropyran.