Nakayama A,
*,
Nakamura T,
Zaima T,
Fujimoto S,
Karanjit S,
Namba K.
*
Tokushima University, Japan
Concise Total Synthesis of Tronocarpine.
Angew. Chem. Int. Ed. 2020;
Key words
(±)-tronocarpine - chippiine alkaloids - tandem cyclization - Dess–Martin oxidation
Significance
Nakayama, Kamba and co-workers report a total synthesis of tronocarpine, a chippiine-type indole alkaloid containing an azabicyclo[3.3.1]nonane core. The synthesis features a tandem cyclization consisting of unsaturated aldehyde formation, intermolecular aldol reaction, and lactamization.
Comment
Indole D was obtained from known precursors in four steps. D gave rise to F and an inseparable mixture of G and H, which could be converted to F in one step. Tandem cyclization was achieved by subsequent treatment with Na2CO3 and Pd/CaCO3. Tronocarpine was obtained in two steps from K.
