Synthesis of (±)-β-Erythroidine

doi:10.1055/s-2006-955656

Synfacts 2007(1): 0003-0003
DOI: 10.1055/s-2006-955656

Synthesis of Natural Products and Potential Drugs

Synthesis of (±)-β-Erythroidine

Contributor(s):Philip Kocienski, Fiona Black

Y. He, R. L. Funk*
Pennsylvania 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

Abstract

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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.

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