Umlagerungen von Tricyclo[3.2.1.1 2,4 ]non‐6‐yl‐, Tricyclo[4.2.1.1 2,5 ]dec‐3‐yl‐ und Tricyclo[4.2.2.1 2,5 ]undec‐3‐yl‐Kationen

Rearrangements of Tricyclo[3.2.1.1 2,4 ]non‐6‐yl, Tricyclo[4.2.1.1 2,5 ]dec‐3‐yl, and Tricyclo[4.2.2.1 2,5 ]undec‐3‐yl Cations The tricyclic ketones 5, 9, 13 , and 24 were prepared by modified or novel routes. The corresponding tosylhydrazones 10, 11, 14 , and 25 were photolyzed in 0.5 N NaOH (NaOD) to generate the title cations 2, 15–17 , and 28 , respectively, by way of diazonium precursors. The distribution of deuterium labels revealed rapid degenerate Wagner‐Meerwein rearrangements of 2 and 28 contrasting the unsymmetrical behavior of the parent bicyclo[3.2.1]oct‐6‐yl cation ( 1 ). The virtually irreversible rearrangement of 17 to 15 , on the other hand, mirrors the preferred chair conformation of 1 . The results with tricyclic carbocations support our previous explanation for the exceptional reactivity of 1 .