He F,
Bo Y,
Altom JD,
Corey EJ.
*
Harvard University, Cambridge, USA
Enantioselective Total Synthesis of Aspidophytine.
J. Am. Chem. Soc. 1999;
121: 6771-6772
DOI:
10.1021/ja9915201
Key words
Haplophyton cimicidum - (–)-aspidophytine - Stork–Danheiser transposition - Corey–Bakshi–Shibata reduction - Ireland–Claisen rearrangement - Malaprade–Lemieux–Johnson cleavage - iminium Hosomi–Sakurai reaction
Significance
The authors present the enantioselective synthesis of (–)-Aspidophytine, isolated from Haplophyton cimicidum leaves and used in Central America as an anticockroach and insecticide. Despite of remarkable achievements towards the synthesis of apsidospermine alkaloids, the complex structure of (–)-aspidophytine remained a challenge for more than 20 years.
Comment
The synthesis commences with the preparation of key intermediate H using a Corey–Bakshi–Shibata reduction followed by Ireland–Claisen rearrangement. Intermediates H and I are combined to form the pentacyclic core structure K in an iminium Hosomi–Sakurai reaction. The synthesis of (–)-aspidophytine is finished via lactonization and installation of the last remaining olefin.
