Development of an enantioselective alkaloid addition to pyrones and studies towards the total synthesis of vinylallene natural products

Pleiomaltinine is an alkaloid-pyrone natural product that was the first of its kind to be isolated in nature. Synthesis of this compound from pleiocarpamine and a reactive quinone methide-like pyrone is described. Furthermore, model compounds have been made that will allow for full testing of this new heterocycle’s biological properties. This process has also been rendered enantioselective using asymmetric organocatalysis with thioureas. Additionally, work has been conducted towards the total synthesis of vinylallene-derived natural products. Progress towards the syntheses of chloropupukeananin, chloropestolide A, pestalofone C, iso-A82775c, and maldoxin isolated from Pestalotiopsis fici are described. All of these compounds are complex and possess biological activities including anti-cancer and anti-HIV. The strategies applied to develop a selective synthesis of reactive vinylallenes are discussed and plans designed to overcome this synthetic challenge are shown in detail. New methodologies are presented along with literature precedent in these areas of research