The generation of pyridynes from diyne nitriles is reported. These cyano-containing precursors are analogs of the triyne substrates typically used for the hexadehydro-Diels-Alder (HDDA) cycloisomerization reactions that produce ring-fused benzynes. Hence, the new processes described represent aza-HDDA reactions. Depending on the location of the nitrile, either 3,4-pyridynes (from 1,3-diynes containing
Potassium Fluoride on Alumina: An Easy Synthesis of 4-Alkylidene-2-Thione-1,3-Oxathiolanes from α-Acetylenic Alcohols
作者:Didier Villemin、Abdelkrim Ben Alloum
DOI:10.1080/00397919208019318
日期:1992.5
Abstract α-acetylenic alcohols and carbon disulfide in the presence on potassium fluoride on alumina without solvent give selectively 4-alkylidene-2-thione- 1,3-oxathiolanes
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