作者:Wei Wang、Jia-Tian Lu、Hao-Li Zhang、Zi-Fa Shi、Jing Wen、Xiao-Ping Cao
DOI:10.1021/jo4023588
日期:2014.1.3
An efficient formal synthesis of (+/-)-cycloclavine is achieved in seven steps and 27% overall yield from the known 2-(4-bromo-1-tosyl-1H-indol-3-yl)acetaldehyde. Key features include an iron(III)-catalyzed aza-Cope-Mannich cyclization and an intramolecular Heck reaction or a self-terminating 6-exo-trig aryl radical-alkene cyclization.
A Modular Formal Total Synthesis of (±)-Cycloclavine
作者:Natalie Netz、Till Opatz
DOI:10.1021/acs.joc.5b02815
日期:2016.2.19
Cycloclavine is a clavine-type Ergot alkaloid noteworthy for its unique pentacyclic skeleton featuring a 3-azabicyclo[3.1.0]hexane substructure. A short convergent route to the racemic alkaloid is described which comprises only eight linear steps and requires only four chromatographic purifications. The two key building blocks can be prepared in high yield from commercially available starting materials
New routes to clavine-type ergot alkaloids. Part 2: Synthesis of the last, so far not yet synthesized member of the clavine alkaloid family, (±)-cycloclavine
Starting from 4-bromo-Uhle's ketone (2), an alkylation step using ethyl 3-methylamino-propionate followed by intramolecular aldol condensation in two steps, transformation of the ester group into a methyl group, and finally cyclopropanation of the 8,9 double bond, resulted in a six-step total synthesis of (±)-cycloclavine (1).