Facile transformation of 1-methoxynaphthalenes to octahydrophenanthrenes application to the total synthesis of (±)-sempervirol methyl ether, (±)-sugiol methyl ether, (±)-nimbiol methyl ether, and (±)-nimbidiol dimethyl ether
general method has been developed for the synthesis of the tricyclic aromatic ketones 4,12,13 and 14 from the 1-methoxynaphthalenes 8,9,10 and 11 respectively. The transformations of the ketones 4,12,13 and 14 into the diterpene ethers (±)-sempervirol methylether (7), (±)-sugiol methylether (15), (±)-nimbiol methylether (16), and (±)-nimbidiol dimethyl ether (17) have been successfully accomplished
New types of concerted domino acylation−cycloalkylation/alkylation−cycloacylation reactions have been described. These processes promoted by methanesulfonic acid−phosphorus pentoxide and concentrated H2SO4, respectively, provide efficient, elegant, and expeditious routes for biologically active naturally occurring diterpenoids, namely (±)-ferruginol (1), (±)-nimbidiol (2), (±)-nimbiol (3), (±)-totarol
已经描述了新型的协调一致的多米诺酰化-环烷基化/烷基化-环酰化反应。分别由甲磺酸-五氧化二磷和浓H 2 SO 4促进的这些过程,为具有生物活性的天然二萜类化合物,即(±)-ferruginol(1),(±)-nimbidiol(2),(±)-丁二酚(3),(±)-戊二醇(4)和ar-松香三烯(5)。
Total synthesis of (±)-<i>epi</i>-stemodan-13α,17-diol
作者:Song Chen、Ting Chen、Guanggen Liu、Xiao Wang、Guili Zhu、Yongjiang Liu、Shaomin Fu、Bo Liu
DOI:10.1039/c9ob00661c
日期:——
Stemodan-13α,17-diol is a natural stemodane-type diterpenoid isolated from Stemodia chilensis. Herein we report the totalsynthesis of its epimer, stemodan-13β,17-diol, by applying titanium-mediated polyene cyclization and iron-catalyzed [5 + 2] cycloaddition as the key transformations to expeditiously install the molecular scaffold.
Sulfenium ion promoted polyene cyclizations in natural product synthesis
作者:Scott R. Harring、Tom Livinghouse
DOI:10.1016/s0040-4039(00)99501-7
日期:1989.1
A four step synthesis of the modified diterpene (±) nimbidiol (3) from (3,4-dimethoxyphenyl)acetonitrile is described which relies on a sulfenium ion promoted polyene cyclization. A key feature of this synthesis is the one flask reductive desulfurization-oxidative decyanation sequence used to convert the post cyclization intermediates 9a,b into prenimbidiol 10.
Influence of electron donating aromatic substituents on the ruthenium tetroxide-catalysed oxidation of (±)-podocarpa-8,11,13-trienes
作者:Sukumar Ghosh、Usha Ranjan Ghatak
DOI:10.1016/s0040-4020(01)88267-3
日期:1992.1
and the diketone 9. Similar oxidation reaction of the hexahydrophenanthrene 7a led to the α, β-unsaturated tricyclic ketone 11a and the tetrahydronaphthalene dicarboxylic anhydride 12. In contrast, 7b produced the diketone 10b and the α,β-unsaturatedketone 11b as the sole isolated products.