General Aspects and Historical Background

Abstract

SummaryThe scope of catalytic enantioselective Friedel-Crafts 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-carbon double bonds and C¼X 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.

Syntheses of Chroman-2-ones and α-Amino Acids through a Diastereoselective Domino Reaction

“…58 Aluminum trichloride is among the most popular reagents applied to catalyze the Friedel−Crafts alkylation. 59 Under various conditions as shown in entries 18−26 of Table 1, the use of 2.5 equiv of AlCl 3 was able to produce the desired chroman-2-one 3f with yields reaching as high as 90% (entry 25) from the starting materials p-methoxyphenol (5f) and (Z)azlactone 6a. It is known that the aluminum chloride is often required in full stoichiometric quantities for catalysis of the Friedel−Crafts reaction.…”

New enantioenriched β‐indolyl ketones as aromatase inhibitors: Unraveling heme–ligand interactions by MD simulation and MMPBSA analysis

“…[27,28] The development of efficient and environmentally friendly asymmetric synthetic methods to access enantiomerically enriched β-indolyl ketones is of great interest in drug discovery efforts. [29] Few Bronsted acids and metal-based chiral catalysts are reported with certain limitations like moderate enantioselectivity and restricted structural features of the Michael acceptors. [30,31] Over the past few years, attention has been focused on amine-based organocatalysts for the asymmetric Michael-type FC alkylation reaction with simple α,β-unsaturated ketones.…”