Isomerization of C12H20 tricyclanes into dimethyl- and ethyladamantanes by the action of complexes of acetyl bromide with aluminum bromide

Superacid‐Catalyzed Reactions

“…Two alternative mechanisms have been suggested. Furthermore, the same catalysts could be The superelectrophilic AcBr-nAlBr 3 complexes, called aprotic organic superacids developed by Vol'pin and co-workers, 119,120 were used in the isomerization of C 12 H 20 tricyclanes with the main component being perhydroacenaphthene to dimethyl-and ethyladamantanes 121 Two mechanistic schemes (Schemes 5.14 and 5.15) via carbocationic intermediates have been proposed by Paquette and Balogh. (ii) n-Butane is protonated by the Brønsted acid to form a carbonium ion intermediate; and either the hydrogen formed is used up to reduce SbF 5 or it loosely remains bound to the ion during the isomerization process.…”

Polyhalomethanes Combined with Lewis Acids in Alkane Chemistry

“…The discovery in the 1980s of the superelectrophilic properties of acylhalide/aluminum halide complexes of the form RCOX•2AlX 3, − as opposed to the classical Friedel−Crafts RCOX•AlX 3 equimolar complexes, − was the high point in electrophilic low-temperature alkane chemistry for that decade. These systems are far superior in their reactivity in alkane reactions to all previously known systems based on either mineral acids or Lewis acids, usually even including the strongest protic superacids. − They have been shown to be extremely active in initiating various transformations of alkanes accompanied by C−C bond cleavage, such as in isomerization, − alkylation, , and oxidative coupling. , In those cases for which cracking reactions can be suppressed, selective single-stage functionalization can be successfully achieved. − ,− …”

“…These systems are far superior in their reactivity in alkane reactions to all previously known systems based on either mineral acids or Lewis acids, usually even including the strongest protic superacids. [98][99][100] They have been shown to be extremely active in initiating various transformations of alkanes accompanied by C-C bond cleavage, such as in 107 isomerization, [108][109][110] alkylation, 111,112 and oxidative coupling. 98,99 In those cases for which cracking reactions can be suppressed, selective single-stage functionalization can be successfully achieved.…”