A Previously Unrecognized 1H-Azepine Synthesis

The 1H‐azepine derivative 1 rather than the cyclohexadienylidenamide 3 was the species obtained by Adams and Brower in 1956, as now revealed by an X‐ray analysis. Assignment of the structure on the basis of spectroscopic data was—and still is—not possible in this case. This finding opens up a simple route for the synthesis of other 2‐cyano‐1H‐azepines.