Kou-Sen Cao, Hong-Xu Bian and Wen-Hua Zheng
Org. Biomol. Chem., 2015,13, 6449-6452
DOI:
10.1039/C5OB00653H,
Communication
The first example of arylboronic acid catalyzed [4 + 3] cycloaddition reaction is reported. 3,5-Bis-(trifluoromethyl) phenylboronic acid is shown to be the best catalyst in this reaction. The method has also enabled the preparation of cyclohepta[b]benzofurans and cyclohepta[b]indoles in excellent yields.