“…In keeping with the complexity of the structure of 22, its chemistry is not entirely straightforward, showing resemblances to alkene and to benzene chemistry. For example, it does not undergo Diels-Alder reactions with simple dienophiles such as maleic anhydride but does react with more reactive dienophiles such as benzyne 75 to give adduct 28 (18%) and with 3,6bis(trifluoromethyl)-1,2,4,5-tetrazine 76 to give products 29 (5%) and 30 (20%) after loss of N 2 (Scheme 6). Some 11-substituted derivatives, which have more localised peripheries, react with alkynes.…”