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
through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetricallenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee)
Construction of Acyclic All‐Carbon Quaternary Stereocenters and 1,3‐Nonadjacent Stereoelements via Organo/Metal Dual Catalyzed Asymmetric Allenylic Substitution of Aldehydes
A novel synthetic strategy for the asymmetric allenylic substitution of aldehydes, which enables the construction of allene-containing acyclic all-carbonquaternarystereocenters and 1,3-nonadjacent stereoelements, has been reported.
We report the first directcatalyticasymmetric N1-functionalization of 1H-indoles via an allenylic alkylation strategy. This transformation produces N-alkylated indoles bearing axial chirality with a stereocenter non-adjacent (β) to the nitrogen. The regioselectivity (N1/C3) of this process can be switched efficiently. We also introduce a new class of tri-substituted allenylic electrophiles.