SCHEDULED MAINTENANCE
Radical additions onto enols and enol ethers as a stratagem in synthesis. Total synthesis of the unique epoxy-lactone (±)-alliacolide found in Marasmius alliaceus
Abstract
The use of intramolecular radical additions onto enols and enol ethers is illustrated in a total synthesis of (±)-alliacolide (3), its methyl ether (39), noralliacolide (25), and several isomeric compounds. The overall strategy for the synthesis of these unique epoxy-lactones is based on (i) spiro-annulation of the tetronic acid ring in the key intermediate (11)via the cyclopentenone (13); (ii) 6-exo-trig radical cyclisation from (11) to the tricycle (10), and (iii) stereocontrolled epoxidation of the β-orientated hydroxy intermediate (10). A novel feature of this synthesis of (±)-alliacolide (3) is the regio- and stereoselective radical cyclisation leading to (10), which introduces three contiguous chiral centres in the correct relative configuration in the tricycle, in a single step.
Please wait while we load your content...
