Total Synthesis of (±)-Norsecurinine
1987; Elsevier BV; Volume: 25; Issue: 1 Linguagem: Inglês
10.3987/s-1987-01-0075
ISSN1881-0942
AutoresClayton H. Heathcock, Thomas W von Geldern,
Tópico(s)Plant-based Medicinal Research
ResumoThe structures of the enantiomeric norsecurinines (2 and 3) have been confirmed by a total synthesis o f ( + ) -2 , starting with L-proiine.The Securineaa alkaloids consist of a total of seventeen compounds isolated from severa i species of the Secur ineqa and Phy I I anthus genera of Euphorbiaceae.These plants have a notably hiqh concentration of alkaloids; in a number of cases the major alkaloid component comorises 0.25% o f the dry plant weight.Z Securinine ( I ) i s the most abundant member of the group.the first to be identiand the only Securineaa alkaloid to have been prepared by total svnthes i ~. ~. ~ Most of the S e c u ~i n e a alkaloids are either securinine stereoisomers or have the securinine skeleton.Four, however.have the rinq-A nor structure.The mast well characterized of this group are the enantiomeric norsecurinines, 26 and 3.'In this Communication, we report a total synthesis of ( 2 1 -2 .which corroborates the assigned structure.OUT retrosynthetic plan is out1 ined in ea 1.The key maneuver was to be construction of three of the four rings by a series of reactions involving tandem Michael and aldoi cyciization.followed by iactoni2ation.10) This x-ray structure was performed by Dr. Fred Hollander of the Berkeley College of Chemistry X-ray Facility (CHEXRAY).
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