Enantioselective Fluoronation With a Simple Organic Catalyst

Significance

Fluorinated molecules are very important in medicinal, agricultural and materials science. This report is the first asymmetric fluorination of aldehydes with a simple catalyst obtaining extremely high ee’s. The use of methyl tert-butyl ether as a solvent proved to be critical to reduce difluorination. The use of N-fluorodibenzenesulfonimide (NFSI), which is a commercially available, stable and easy to handle fluoride source, is an excellent complement to the already simple catalyst system. The optically active α-fluorinated aldehydes were directly reduced to the corresponding α-fluorinated alcohols since the α-fluorinated aldehydes are unstable and more volatile than starting materials.