Abstract:
Treatment of an alkene with a thallium (I) carboxylate and iodine has been shown to give the corresponding-iodocarboxylate in high yield. The reactions are region-specific and offer an alternative to the Prevost reaction. The intramolecular version of this reaction has been found to provide a superior procedure for iodolactonisation which allows the products of kinetic control to be obtained. Mechanisms for both the inter- and intramolecular reactions are proposed and compared with those accepted for related reactions.
Routes available for synthesis of naturally occurring tetracycloxides have been reviewed. Exploration of a new route utilising readily available anthraquinones to provide the appropriately substituted BCD ring systems has been initiated. Methods have been developed for the generation of an aldehyde at C2 in anthraquinones either by direct introduction or by oxidation of a benzylic methyl. Elements suitable for elaboration to the A ring have been attached in model systems using a 1,3-dipolar cycloaddition process.