K. Nemoto, Satoru Onozawa, Naoki Egusa
Aug 5, 2009
Citations
0
Influential Citations
39
Citations
Journal
Tetrahedron Letters
Abstract
Abstract The Lewis acid-mediated carboxylation of arenes with CO 2 has been successfully applied to 1-substituted indoles and pyrroles by using dialkylaluminum chlorides instead of aluminum trihalides. Thus, the carboxylation of 1-methylindoles, 1-benzyl-, and 1-phenylpyrroles proceeds regioselectively with the aid of an equimolar amount of Me 2 AlCl under CO 2 pressure (3.0 MPa) at room temperature to afford the corresponding indole-3-carboxylic acids and pyrrole-2-carboxylic acids in 61–85% yields, while the same treatment of 1,2,5-trimethylpyrrole affords the 3-carboxylic acid in 52% yield.