Concise asymmetric syntheses of streptazone A and abikoviromycin

27 November 2020, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Streptazone A and abikoviromycin are related alkaloids that both feature an unusual arrangement of reactive functionalities within an underlying compact tricyclic ring system. Here, we report a highly concise asymmetric synthesis of both natural products. The developed route first constructs another member of the streptazones, streptazone B1, using a rhodium-catalyzed distal selective allene-ynamide Pauson-Khand reaction as the key transformation. A regio- and enantioselective epoxidation under chiral phase-transfer catalytic conditions was then achieved to directly make streptazone A in 8 steps overall. A chemoselective, iridium-catalyzed reduction of the enaminone-system was employed to make abikoviromycin in one additional step. Studies of the intrinsic reactivity of streptazone A towards the cysteine mimic, N-acetylcysteamine, revealed unanticipated transformations, resulting in thiol conjugation to both the hindered tertiary carbon of the double allylic epoxide and in bis-thiol conjugation which may proceed via formation of a cyclopentadienone intermediate. With flexible access to these compounds, studies aimed to identify their direct biological targets are now possible.


natural products
total synthesis
asymmetric synthesis
electrophilic compounds

Supplementary materials

Supporting information


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