Addition of benzyne to bicyclo[4.2.1]nona-2,4,7-trien-9-one and 1,6-methano[10]annulene

Annulenes, 1980–2000

“…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.…”