An expeditious route to the potential immunosuppressive lead compound ivorenolideB (1) is described, which relies on the formation of the distinctive 1,3‐diyne subunit embedded into the 17‐membered framework of this target by ring‐closing alkyne metathesis (RCAM). This key transformation was accomplished with the aid of the molybdenum alkylidyne complex 7, which turned out to be compatible with the
Reactions of HDDA-Derived Benzynes with Sulfides: Mechanism, Modes, and Three-Component Reactions
作者:Junhua Chen、Vignesh Palani、Thomas R. Hoye
DOI:10.1021/jacs.6b01025
日期:2016.4.6
We report here reactions of alkyl sulfides with benzynes thermally generated by the hexadehydro-Diels-Alder (HDDA) cycloisomerization. The initially produced 1,3-betaine (o-sulfonium/aryl carbanion) undergoes intramolecular proton transfer to generate a more stable S-aryl sulfur ylide. This can react in various manners, including engaging weak acids (HA) in the reaction medium. This can produce transient
Synthesis of 1,3-Diynes via Cadiot–Chodkiewicz Coupling of Volatile, in Situ Generated Bromoalkynes
作者:Phil C. Knutson、Haleigh E. Fredericks、Eric M. Ferreira
DOI:10.1021/acs.orglett.8b02975
日期:2018.11.2
A convenient Cadiot–Chodkiewicz protocol that facilitates the use of low molecular weight alkyne coupling partners is described. The method entails an in situ elimination from a dibromoolefin precursor and immediate subjection to copper-catalyzed conditions, circumventing the hazards of volatile brominated alkynes. The scope of this method is described, and the internal 1,3-diyne products are preliminarily
The Phenol–Ene Reaction: Biaryl Synthesis via Trapping Reactions between HDDA-Generated Benzynes and Phenolics
作者:Juntian Zhang、Dawen Niu、Vincent A. Brinker、Thomas R. Hoye
DOI:10.1021/acs.orglett.6b02830
日期:2016.11.4
Benzynes produced thermally by the cycloisomerization of triyne-containing precursors [i.e., by the hexadehydro-Diels–Alder (HDDA) reaction] react with phenols at the carbon ortho to the hydroxyl in an enelike fashion. Following tautomerization of the intermediate cyclohexadienones, this produces biaryl derivatives. DFT calculations of model reactions support this mechanistic interpretation. Substituted
作者:Raphael J. Zachmann、Kenzo Yahata、Mira Holzheimer、Maxime Jarret、Cornelia Wirtz、Alois Fürstner
DOI:10.1021/jacs.2c12529
日期:2023.2.1
might need to be revised. Indeed, re-examination of the published spectra cast doubts as to the constitution of the fused/spirotricyclic BCD-ring system in the core. To clarify this issue, a flexible synthesis blueprint was devised that allowed us to obtain the originally proposed structure as well as the most plausible amended structure. The key to success was late-stage gold-catalyzed spirocyclization