A convenient route to 1,3-diynes using ligand-free Cadiot-Chodkiewicz coupling reaction at room temperature under aerobic conditions
作者:Sujatha Asha、Sasidharan Anjana、Anns Maria Thomas、Minu Elizabeth Thomas、K. R. Rohit、K. Keerthi Krishnan、Sankuviruthiyil M Ujwaldev、Gopinathan Anilkumar
DOI:10.1080/00397911.2018.1554142
日期:2019.1.17
Abstract In this study, we report a copper-catalyzed ligand-free Cadiot-Chodkiewicz couplingreaction. No additives or ligands are required for this Cu-catalyzed C(sp)-C(sp) couplingreaction of terminal alkynes with alkynyl halides. The low cost of copper catalyst, excellent yield of the products, suppression of side-products and mild reaction conditions are the major advantages of this protocol.
Highly efficient synthesis of unsymmetrical 1,3-diynes from organoalane reagents and alkynyl bromides mediated by a nickel catalyst
作者:Song Mo、Xue-Bei Shao、Gang Zhang、Qing-Han Li
DOI:10.1039/c7ra02758c
日期:——
Highlyefficient and simple cross-coupling reactions of alkynylbromides with organoalane reagents for the synthesis of unsymmetrical 1,3-diynes derivatives using Ni(OAc)2 (2–5 mol%)/(o-furyl)3P (4–10 mol%) as a catalyst are reported. Excellent yields (up to 94%) were obtained for a wide range of substrates at rt or 60 °C for 2–3 h in Et2O or toluene.
Terminal arylbutadiynes, derived from 6-aryl-3,5-hexadin-2-ols, undergo a ready palladium-catalyzed coupling with activated aryl halides in the presence of a phase transfer catalyst to unsymmetrical diarylbutadiynes, not easily available by other coupling procedures.
(Pyridinylmethylidene)dithioles: synthesis, structure, and reactivity
作者:Kevin T. Potts、Susan A. Nye、Kennith A. Smith
DOI:10.1021/jo00040a032
日期:1992.7
Spectral characteristics, an X-ray crystal structure, and molecular orbital calculations indicate that (pyridinylmethylidene)dithioles 3, prepared from butadiynyl precursors 4 and hydrogen sulfide in basic methanol, are analogous in their bonding to the parent 1-aza-6,6a-lambda-4-dithiapentalenes 1 which, according to ab initio studies at the Hartree-Fock level, is best represented as an (iminomethylidene)dithiole. An interaction between the sulfur and the nitrogen atoms is evident from the significant polarization of the S-S bond in those isomers where the nitrogen is proximal to the dithiole moiety. A comparison of the calculated structures of 1 and 3 with experimental data, as well as preliminary calculations on the related system trithiapentalene 2, suggest that ab initio methods using a single determinant are inadequate to describe these hypervalent sulfur systems. For example, an asymmetric structure is calculated to be the minimum energy form for 2 in contradiction to experimental results. Electrophilic substitutions, ring rearrangement, and reaction with electron acceptors are described for 3.