Studies of a Diazo Cyclopropanation Strategy for the Total Synthesis of (-)-LundurineA

The bioactive Kopsia alkaloids lundurinesA-D are the only natural products known to contain indolylcyclopropane. Achieving their syntheses can provide important insights into their biogenesis, as well as novel synthetic routes for complex natural products. Asymmetric total synthesis of (-)-lundurine...

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Bibliographic Details
Published in:Chemistry : a European journal 2015-09, Vol.21 (38), p.13284-13290
Main Authors: Huang, Hong-Xiu, Jin, Shuai-Jiang, Gong, Jin, Zhang, Dan, Song, Hao, Qin, Yong
Format: Article
Language:English
Subjects:
Alkaloids
Asymmetry
Cascades
Chemistry
Hydrazones
Insertion
Natural products
Strategy
Synthesis
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Summary:The bioactive Kopsia alkaloids lundurinesA-D are the only natural products known to contain indolylcyclopropane. Achieving their syntheses can provide important insights into their biogenesis, as well as novel synthetic routes for complex natural products. Asymmetric total synthesis of (-)-lundurineA has previously been achieved through a Simmons-Smith cyclopropanation strategy. Here, the total synthesis of (-)-lundurineA was carried out using a metal-catalyzed diazo cyclopropanation strategy. In order to avoid a carbene CH insertion side reaction during cyclopropanation of [alpha]-diazo- carboxylates or cyanides, a one-pot, copper-catalyzed Bamford-Stevens diazotization/diazo decomposition/cyclopropanation cascade was developed, involving hydrazone. This approach simultaneously generates the C/D/E ring system and the two chiral quaternary centers at C2 and C7.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.201502011