Highly Active Au(I) Catalyst for the Intramolecular <i>e</i><i>xo</i>-Hydrofunctionalization of Allenes with Carbon, Nitrogen, and Oxygen Nucleophiles
作者:Zhibin Zhang、Cong Liu、Robert E. Kinder、Xiaoqing Han、Hua Qian、Ross A. Widenhoefer
DOI:10.1021/ja062045r
日期:2006.7.19
Au-catalyzed intramolecularhydroalkoxylation within minutes at room temperature to form the corresponding oxygen heterocycles in good yield with high exo-selectivity. 2-Allenyl indoles underwent Au-catalyzed intramolecular hydroarylation within minutes at room temperature to form 4-vinyl tetrahydrocarbazoles in good yield. Au-catalyzed cyclization of N-allenyl carbamates, allenyl alcohols, and 2-allenyl
Gold(I)-Catalyzed Enantioselective [4 + 2]-Cycloaddition of Allene-dienes
作者:Ana Z. González、F. Dean Toste
DOI:10.1021/ol902622b
日期:2010.1.1
An enantioselective gold(I)-catalyzed intramolecular [4 + 2]-cycloaddition of allenes and dienes is reported. The reactions allow for the asymmetric synthesis of trans-hexahydroindenes and pyrrolidine products using C3-symmetric phosphitegold(I) and ortho-arylphosphoramiditegold(I) complexes as catalysts, respectively.
(Alkylthio)alkynes as Addends in the Co(0) Catalyzed Intramolecular Pauson-Khand Reaction. Substituent Driven Enhancements of Annulation Efficiency and Stereoselectivity
作者:Brian L. Pagenkopf、David B. Belanger、Donogh J. R. O'Mahony、Tom Livinghouse
DOI:10.1055/s-2000-6301
日期:——
Compared to terminal alkynes, (methylthio)alkynes are generally superior substrates for the thermally promoted, Co2(CO)8 catalyzed Pauson-Khand reaction of enynes and allenynes, providing enones in higher yields and with enhanced diastereoselectivity. Improvements in yield dependent upon the use of 2,2,2-trifluoroethanol as co-solvent and an apparent preference for endo selectivity with (ethoxy)alkynes are also disclosed.
Palladium(0)-catalyzed reaction of allene-substituted allylic carboxylates 3-8 employing 2-5 mol % of Pd(dba)(2) in refluxing toluene leads to the carbocyclization and elimination of carboxylic acid to give bicyclo[4.3.0]nonadiene and bicyclo[5.3.0]decadiene derivatives (12-17). The carbon-carbon bond formation is stereospecific, occurring syn with respect to the leaving group. Addition of maleic anhydride
Allenynes having malonate-based tethers reacted with arylboronic acids in the presence of a rhodium(I) catalyst to sequentially form three carbon–carbon bonds, and arylated bicyclic skeletons were constructed in a stereoselective manner.