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DOI: 10.1055/s-2006-955656
Synthesis of (±)-β-Erythroidine
Rezensent(en):Philip Kocienski, Fiona BlackPennsylvania State University, University Park, USA
Total Syntheses of (±)-β-Erythroidine and (±)-8-oxo-β-Erythroidine by an Intramolecular Diels-Alder Cycloaddition of a 2-Aminoacrolein
Org. Lett. 2006, 8: 3689-3692
Publikationsverlauf
Publikationsdatum:
15. Dezember 2006 (online)
Key words
retro-Diels-Alder reaction - Diels-Alder cycloaddition - Heck reaction - 6-electrocyclization
Significance
A 13-step synthesis of the erythrinan alkaloid (±)-β-erythroidine is reported. A Diels-Alder cycloadditon, an intramolecular Heck cyclization and an electrocyclic ring closure are employed in the construction of the tetracyclic ring system.
Comment
Upon heating in refluxing toluene, amidoxin D underwent a retrocycloaddition and Diels-Alder cycloaddition to afford F in 66% yield. Ester G was saponified and the corresponding dienoic acid derivative heated in refluxing toluene to effect a 6π-electrocyclic ring closure. Introduction of the C3 oxygen was achieved diastereoselectively with singlet oxygen to give J, which was converted into β-erythroidine in three steps.