Nickel-Catalyzed [2+2+2] Cycloaddition of Diynes and Cyanamides
作者:Ryan M. Stolley、Michael T. Maczka、Janis Louie
DOI:10.1002/ejoc.201100428
日期:2011.7
A variety of bicyclic N,N-disubstituted 2-aminopyridines have been prepared from diynes and cyanamides by nickel-catalyzed [2+2+2] cycloaddition reactions. The reactions proceeded at room temperature with low catalyst loading to afford 2-aminopyridines in good to excellent yields. The method is amenable to both internal and terminal diynes and proceeds in a regioselective manner. A number of cyanamides
Cyclization of diacetylenes to E,E exocyclic dienes. Complementary procedures based on titanium and zirconium reagents
作者:William A. Nugent、David L. Thorn、R. L. Harlow
DOI:10.1021/ja00243a036
日期:1987.4
La cyclisation intramoleculaire de composes diyniques a ete effectuee en utilisant l'une des combinaisons de reactifs: Cp 2 TiCl 2 /PMePh 2 /Na(Hg) ou Cp 2 ZrCl 2 /Mg/HgCl 2
La cyclisation intramoleculaire de composes diyniques a ete effectuee en utilisant l'une des combinaisons de reactifs: Cp 2 TiCl 2 /PMePh 2 /Na(Hg) ou Cp 2 ZrCl 2 /Mg/HgCl 2
A Nickel-Catalyzed Route to Pyridines
作者:Michael M. McCormick、Hung A. Duong、Gang Zuo、Janis Louie
DOI:10.1021/ja0508931
日期:2005.4.1
A mild and general route for preparing pyridines from nitriles and diynes is described. Ni/imidazolyidene complexes were used to mediate cyclization alkynes and both aryl and alkyl nitriles at ambient temperature. In addition, the efficacy of this protocol allows for the preparation of a fused seven-membered pyridone and for intermolecular cyclizations. When an asymmetrical diyne was employed, cyclization
Palladium/Nickel-Cocatalyzed Cycloaddition of 1,3-Dehydro-<i>o</i>-Carborane with Alkynes. Facile Synthesis of C,B-Substituted Carboranes
作者:Zaozao Qiu、Zuowei Xie
DOI:10.1021/ja1058789
日期:2010.11.17
o-Carboryne (1,2-dehydro-o-carborane) has been reported as a very reactive intermediate and regarded as a three-dimensional relative of benzyne, whereas the 1,3-dehydro-o-carborane has remained elusive. In this article, we present the preparation of 1,3-dehydro-o-carborane from 3-iodo-1-lithio-o-carborane mediated by palladium(0). This reactive intermediate can be trapped by alkynes via Pd/Ni-cocatalyzed
Nickel-Catalyzed Regioselective [2+2+2] Cycloaddition of Carboryne with Alkynes
作者:Zaozao Qiu、Sunewang R. Wang、Zuowei Xie
DOI:10.1002/anie.201001249
日期:2010.6.21
A View [2+2+2] a Kill: For the first time, nickel‐catalyzed [2+2+2] cycloaddition reactions of alkynes or diynes with carboryne using 1‐iodo‐2‐lithiocarborane as a precursor have been achieved. The mechanism is proposed after the structural confirmation of the key intermediate, nickelacyclopentene.