Table I. Of note is that specially prepared “acid-free” 5 does not give acid-catalyzed rearrangement products of 3. Compound 5, prepared in the usual manner6 and not carefully recrystallized, contains some hydrogen bromide as evidenced by the evolution of a gas acidic to litmus when 5 is heated in acetonitrile. Results with 2 parallel those from 5 (see Table 11), although under these conditions indenone formation competes. Methanol and ...
