General Aspects and Historical Background

The scope of catalytic enantioselective Friedel\u2013Crafts alkylations is expanding rapidly and since the seminal papers appeared in the mid 1980s, numerous examples featuring enantioselectivities higher than 90% have been published. At present, nearly all the organic compounds displaying electrophilic character have been reacted with aromatic systems in FC-type alkylation reactions. However, the typology of reagents becomes slightly narrower if we limit the survey to approaches that employ chiral catalysts capable of traducing stereochemistry in the final products. Activated as well as unactivated carbon\u2013carbon double bonds and C\ubcX frameworks characterize the most used classes of electrophilic agents, that are generally combined with privileged chiral organometallic and organic catalysts. It is also worth mentioning the actual distribution of enantioselective FC processes based on the type of aromatic system employed. Interestingly, highly reactive electron-rich arenes (pyrrole and indole) still constitute almost 80% of catalytic enantioselective FC-processes, while asymmetric transformations of benzene-like compounds are quite undeveloped