Highly Regio‐, Diastereo‐, and Enantioselective Assembly of Azepino[2,3‐b]indoles viaPalladium‐Catalyzed [4 + 3] Cycloaddition†.

Summary of main observation and conclusion: A palladium‐catalyzed asymmetric [4 + 3] cycloaddition of trimethylenemethanes and indoline‐derived aza‐dienes has been developed. The potential [3 + 2] side pathway was completely suppressed in the process. This protocol provides an efficient access to azepino[2,3‐b]indoles bearing two vicinal stereocenters in generally excellent diastereo‐ and enantioselectivities (up to > 20 : 1 dr, 99% ee). [ABSTRACT FROM AUTHOR]