Total synthesis of dehydroambliol-A and its unnatural Z isomer
摘要:
Convergent total syntheses of dehydroambliol-A (1a), its unnatural Z isomer 1b, and ambliofuran (2) are described. The syntheses utilized 2-(3'-furyl)-1,3-dithiane (6) as a common intermediate. Analysis of their proton and carbon magnetic resonance spectra confirm that in the natural product dehydroambliol-A and in synthetic dehydroambliol-A the DELTA-7-bond possesses the E geometry, while in the unnatural isomer of dehydroambliol-A, the DELTA-7-bond is of the Z configuration.
A Concomitant Allylic Azide Rearrangement/Intramolecular Azide–Alkyne Cycloaddition Sequence
作者:Rakesh H. Vekariya、Ruzhang Liu、Jeffrey Aubé
DOI:10.1021/ol500011f
日期:2014.4.4
An intramolecular Huisgen cycloaddition of an interconverting set of isomeric allylicazides with alkynes affords substituted triazoles in high yield. The stereoisomeric vinyl-substituted triazoloxazines formed depend on the rate of cycloaddition of the different allylicazide precursors when the reaction is carried out under thermal conditions. In contrast, dimerized macrocyclic products were obtained
Total Synthesis of (±)-Brussonol and (±)-Komaroviquinone via a Regioselective Cross-Electrophile Coupling of Aryl Bromides and Epoxides
作者:Anees Ahmad、Antonio C. B. Burtoloso
DOI:10.1021/acs.orglett.9b02221
日期:2019.8.2
The short and stereoselective syntheses of diterpenes (±)-brussonol and (±)-komaroviquinone, via a Ni-catalyzed epoxide ring-opening approach in the presence of aryl halides, is described. Key steps involve the effective preparation of a challenging hemiacetal intermediate in a single operation, followed by a highly efficient BF3·OEt2-catalyzed Friedel–Craft alkylation, to construct the tricyclic skeleton
Reductive Radical Annulation Strategy toward Bicyclo[3.2.1]octanes: Synthesis of <i>ent</i>-Kaurane and Beyerane Diterpenoids
作者:Junming Zhuo、Chunlin Zhu、Jinbao Wu、Zijian Li、Chao Li
DOI:10.1021/jacs.1c11623
日期:2022.1.12
Here we report a general [3 + 2] radical annulation that allows the facile construction of bicyclo[3.2.1]octane motifs in ent-kaurane- and beyerane-type diterpenoids. This radical annulation is difficult to control but was realized by harnessing an unprecedented and counterintuitive effect of TEMPO. Eleven natural products with a wide array of oxidation states are easily prepared, demonstrating the
A facile entry to bicyclic γ-lactones and a short synthesis of (±)-dihydroactinidiolide
作者:T.K. Chakraborty、S. Chandrasekaran
DOI:10.1016/s0040-4039(01)81319-8
日期:1984.1
A highly useful mode of access to bicyclic γ-lactones 3 from tert-hydroxyolefins 2 with chromium(V) reagent or PCC and its application to the synthesis of (±)-dihydroactinidiolide are described.