Fig. 4: Substrate scope expanding of the nucleophilic asymmetric fluorinations using BF3·Et2O as the fluorine source.

Reactions were conducted on a 0.2 mmol scale with 10.0 equivalents of BF3·Et2O in C6H5F (8.0 mL) at −42 °C for 20 h; isolated yields are reported. *CIC2 was applied as the catalyst for the formation of 53b and 54b. The ee values were determined by chiral HPLC analysis. Me, methyl; t-Bu, tert-butyl; Et, ethyl.