アイテム詳細

要旨

The Pictet-Spengler reaction of 2-arylethylamines with aldehydes is a powerful methodology for the redox-neutral synthesis of partly hydrogenated nitrogen heterocycles. Especially tetrahydro-β-carbolines and tetrahydroisoquinolines represent valuable synthetic targets due to the prevalence of the respective molecular frameworks in naturally occurring alkaloids. The work presented within this thesis describes the development of a catalytic asymmetric Pictet-Spengler reaction toward tetrahydroisoquinolines – a product class that had been largely inaccessible via this route. Furthermore, the utilization of the available products in the biomimetic formal or total synthesis of eleven distinct natural products from diverse alkaloid classes was accomplished. Key to the development of a general methodology was the design and synthesis of bespoke imidodiphosphorimidate catalysts featuring electron-rich substituents that offered unprecedentedly high reactivity and selectivity in the system under study. The mechanistic nuances of the reaction were studied experimentally through in-depth kinetic analyses. Our investigation thus provides insights into the overall reaction mechanism as well as specific interactions offered by the optimal catalysts. Finally, further studies were directed toward the development of a catalytic asymmetric Pictet-Spengler reaction of electronically unbiased phenethylamines.