New synthetic routes towards various α-fluorinated aryl ketones and their enantioselective reductions using bakerʹs yeast

Highly electrophilic dichlorofluoromethyl aryl ketones were obtained by oxidation of dichlorofluoromethyl aryl alcohols. Subsequent dechlorination of these ketones using sodium formaldehyde sulfoxylate (Rongalite) and reductive dehalogenating system SnCl2/Al led to various fluoromethyl aryl ketones and chlorofluoromethyl aryl ketones, respectively. Asymmetric reductions of these fluorinated ketones using the inexpensive bakerʹs yeast produced the corresponding fluoromethyl aryl alcohols with different enantioselectivities.