Gallium(III)‐Catalyzed Three‐Component (4+3) Cycloaddition Reactions

Direct approach to indoles: The title reaction generates cyclohepta[b]indole derivatives in a single step at room temperature (see scheme). Exclusion of air or moisture is not required. DFT calculations support a stepwise cyclization event, and the versatility of the method is demonstrated by providing quick access to a library of cyclohepta[b]indole analogues.