Synthetic Studies on Altemicidin: Stereocontrolled Construction of the Core Framework

The stereoselective synthesis of the key intermediate for altemicidin has been accomplished. The synthesis commenced with a bicyclo[3.3.0] framework, which was readily obtained via an intramolecular C-H insertion reaction. A Curtius rearrangement was employed as a key step to stereoselectively construct the beta-hydroxyl alpha-disubstituted-alpha-amino acid structure. Synthesis of vinylogous urea was achieved using hydrolysis of nitrile intermediate.