The effect of DBU on the tandem oxy-Cope/ene reaction and total synthesis of (+)-Arteannuin M.

Tandem reactions have been proven to be powerful methods for creating new types of carbon-carbon bonds in organic synthesis. One such type of reaction is the oxy-Cope/ene reaction of 1,2-divinylcyclohexanols. This reaction has been shown to be a highly diastereoselective method for creating polycyclic compounds with tertiary alcohols at a ring junction. Unfortunately, in many of the previously reported cases, undesired retroene products were also observed.* A new method has been developed that increases the ratio of oxy-Cope/ene with respect to retroene product that involves the use of DBU as a co-solvent in this reaction. This methodology was applied to intermediate 109 (readily obtainable from (+)-limonene) as a key step in the total synthesis of (+)-Arteannuin M (128), a potential drug for the treatment of malaria.* *Please refer to dissertation for diagrams