A recent paper of Dr. Frank D. King and co-workers (from University College London) was dealing with the acid-mediated cyclisation patterns of N-cinnamoyl-1-naphtylamines.1 While most results were matching what one would expect, the authors observed two new products appearing when the nitrogen atom was bearing a benzyl group. They proposed structures for these unexpected products, so the question is, what would you propose for the mechanism?
1. J. Org. Chem. 2013, 78, 10938-10946 link