We present a full account of our synthetic studies on the racemic DEFGH-ring moiety of physalins, featuring domino ring transformation of a tricyclic key intermediate. We also report the results of a detailed mechanistic examination of the domino ring transformation, as well as a reoptimization of the 2,3-Wittig rearrangement and methylation steps. Furthermore, we have newly established a method for the preparation of an optically active synthetic intermediate by enzymatic kinetic resolution. Our work provides access to both natural and nonnatural right-side physalin structures.
Morita, M., Kojima, S., Ohkubo, M., Koshino, H., Hashizume, D., Hirai, G., Maruoka, K., & Sodeoka, M. (2017). Synthesis of the Right‐Side Structure of Type B Physalins. Israel Journal of Chemistry, 57(3-4), 309-318. https://doi.org/10.1002/ijch.201600110