Revision of the structure of strychnochromine

Construction of Various Bridged Polycyclic Skeletons by Palladium‐Catalyzed Dearomatization

“…One carbocyle of compound 6 was easily cleaved through selective hydrogenation, followed by oxidation with KMnO 4 / NaIO 4 to form carboxylic acid 7, which constitutes the bridged tricyclic core of strychnochromine. [18] Dracaenones, [6b] isolated from Dracaena loureiri, are a family of natural products featuring bridged homoisoflavan skeleton with promising quinone oxidoreductase 1 (NQO1)-Scheme 1. Facile syntheses of various bridged polycyclic skeletons by palladium-catalyzed dearomatization.…”

Palladium/l-Proline-Catalyzed Enantioselective α-Arylative Desymmetrization of Cyclohexanones

“…The resulting unique bridged ring system is analogous to the important morphan scaffold (2-azabicyclo[3.3.1]­nonane) and frequently occurs in many natural products, such as sespenine, aspernomine, and strychnochromine (Figure ). More importantly, an α-carbonyl tertiary stereogenic center is generated in this bridged ring system, and its racemization is prevented by the rigid structural property.…”

Diastereoselective Synthesis of 3,4-Benzomorphan Derivatives via Tandem [5 + 1]/Hemiaminalization of (2-Aminoaryl)divinyl Ketones

“…The morphan ring system is present in many natural products, such as morphine, and some synthetic compounds with analgesic activity . 3,4-Benzomorphan, a related morphan skeleton with potential biological activity, can also be found in natural products, such as strychnochromine (an unusual alkaloid from Strychnos gossweileri) and aspernomine (a cytotoxic anti-insectan metabolite from the sclerotia of Aspergillus nomius). Although numerous methods for the synthesis of the morphan structure have been developed, , only few reports exist in the literature on the construction of 3,4-benzomorphan scaffolds. ,− In 2001, Bonjoch’s group reported a Pd-mediated intramolecular coupling of aryl iodide with the α-carbon of a carbonyl group to give 3,4-benzomorphan derivatives (Scheme , eq 1) .…”