Synthesis of Bicyclic Hydroxy Lactone Intermediates toward (-)-Tetrodotoxin

All articles of this category Tetrodotoxin has a characteristic orthoester (hemilactal) existing in equilibrium with the corresponding α-hydroxy lactone. This paper deals with efficient syntheses of 2 analogous hydroxy lactones. The first one includes trans-lactonization accompanied by opening of epoxide. The second synthesis ends up with oxidative cleavage of vinyl group with RuO 4 as crucial step for this lactone. tetrodotoxin - α-hydroxy lactone - ruthenium oxidation - zinc copper reduction - epoxide opening