Abstract
Herein, we present a 16-step synthetic route to norzoanthamine that features three
pivotal photochemical transformations. A photoinduced dearomative 6π-desymmetrization
is employed to access the ABC tricyclic core structure. To address the challenge of
constructing the C9–C22 vicinal all-carbon quaternary stereocenters, [2+2]-photocycloaddition,
visible-light-induced decarboxylative borylation, and a retro-aldol reaction are strategically
employed. The assembly of the norzoanthamine core framework is achieved through a
one-pot cascade transformation, combining global deprotection, biomimetic cyclization,
and epimerization at C21, resulting in an efficient and concise synthesis of norzoanthamine.
1 Introduction
2 Total Synthesis of Norzoanthamine
3 Conclusion
Key words
norzoanthamine - total synthesis - marine alkaloids - photocycloaddition - anti-osteoporosis
