The indole derivative shown below is labeled with tritium in the position shown. When it is cyclised with the Lewis acid boron trifluoride, the label may be found with equal probability in the two places shown. Provide a mechanism for this reaction that accounts for this observation.

Transcribed Image Text:

Эн (50:50) BF3 H H H. 3. Эн (50:50) BF3 H H H. 3.