Enantioselective Friedel-Crafts Alkylations of α,β-Unsaturated 2-Acyl Imidazoles
D. A. Evans*, K. R. Fandrick, H. Song
Harvard University, Cambridge, USA
21 September 2005 (online)
Although there are examples of asymmetric Friedel-Crafts alkylations, the use of the α,β-unsaturated 2-acyl imidazoles as acceptor is a new finding. This substrate-catalyst combination allows the reaction to be performed at 0 °C, providing high enantioselectivities with low catalyst loadings. The resulting 2-acyl imidazole residue can be transformed into various carboxylic acid derivatives via methylation and nucleophilic additions.