Microwave-Assisted Solid-Acid-Catalyzed Friedel-Crafts Alkylation and Electrophilic Annulation of Indoles Using Alcohols as Alkylating Agents
作者:Béla Török、Aditya Kulkarni、Phong Quang
DOI:10.1055/s-0029-1217052
日期:2009.12
Alcohols are considered environmentally benign alkylating agents since the only by-product generated in their reactions is water. Herein, we report a microwave-assisted Friedel-Crafts alkylation and electrophilic annulation of indoles using alcohols as alkylating agents. Alkylation of indoles using tert-butyl alcohol gives 3-substituted tert-butylindoles. A domino electrophilic annulation/aromatization of indoles using hexane-2,5-diol results in the formation of substituted carbazoles. The reaction is catalyzed by a strong, solid-acid catalyst montmorillonite K-10. The products were obtained in good yields and high selectivities.
Solvent-Free Solid Acid-Catalyzed Electrophilic Annelations: A New Green Approach for the Synthesis of Substituted Five-Membered N-Heterocycles
作者:Mohammed Abid、Andrew Spaeth、Béla Török
DOI:10.1002/adsc.200606200
日期:2006.10
An effective microwave-induced, solid acid-catalyzed, environmentally benign synthesis of substituted pyrroles, indoles and carbazoles under solvent-free conditions is described. The new synthetic methodology is based on the use of a considerably strong solid acid, K-10 montmorillonite. Both the cyclialkylation of amines and annelation of pyrroles and indoles have been completed within minutes and