484061-53-2Relevant academic research and scientific papers
Total Syntheses of Lepadiformine Marine Alkaloids with Enantiodivergency, Utilizing Hg(OTf)2-Catalyzed Cycloisomerization Reaction and their Cytotoxic Activities
Nishikawa, Keisuke,Yamauchi, Kengo,Kikuchi, Seiho,Ezaki, Shinnosuke,Koyama, Tomoyuki,Nokubo, Haruka,Matsumura, Kunihiro,Kodama, Takeshi,Kumagai, Momochika,Morimoto, Yoshiki
, p. 9535 - 9545 (2017)
The enantioselective total syntheses of lepadiformine marine alkaloids, azatricyclic natural products isolated from marine tunicates, were completed. These alkaloids have a unique chemical structure characterized by the trans-1-azadecalin (AB ring system) fused with the spirocyclic ring (AC ring system). Here we found that a cycloisomerization reaction from functionalized linear substrates to a 1-azaspiro[4.5]decane framework corresponding to the AC ring in lepadiformines is promoted by a catalytic amount of mercury(II) triflate (Hg(OTf)2). The total syntheses of (?)-lepadiformines A and B were achieved in 28 % and 21 % overall yields, respectively, through the novel cycloisomerization reaction. The syntheses of (+)- and (?)-lepadiformine C hydrochloride salts also enabled us to determine the absolute configuration of natural lepadiformine C. It has been found that a phenomenon of enantiodivergence occurs in lepadiformine alkaloids from a single species of marine tunicate, Clavelina moluccensis. The cytotoxic activities of synthesized lepadiformine hydrochloride salts and their synthetic intermediates were evaluated.
Total synthesis of the tricyclic marine alkaloids (-)-lepadiformine, (+)-cylindricine C, and (-)-fasicularin via a common intermediate formed by formic acid-induced intramolecular conjugate azaspirocyclization
Abe, Hideki,Aoyagi, Sakae,Kibayashi, Chihiro
, p. 1473 - 1480 (2007/10/03)
A very short and efficient enantioselective total synthesis of the tricyclic marine alkaloids (-)-lepadiformine (3), (+)-cylindricine C (1c), and (-)-fasicularin (4) has been developed utilizing the formyloxy 1-azaspiro[4.5]decane 5 as a common intermedia
Total synthesis of the natural enantiomer of (-)-lepadiformine and determination of its absolute stereochemistry
Abe, Hideki,Aoyagi, Sakae,Kibayashi, Chihiro
, p. 3017 - 3020 (2007/10/03)
A short synthesis: The naturally occurring (-)-lepadiformine ((-)-3) was prepared in nine steps in 31.4% overall yield. The key step involved the formation of 2 by the spirocyclization of the N-acyliminium ion generated from 1. Furthermore, HPLC analysis
