Ball-Milling Assisted Synthesis of Monofluoroalkenes.

A solvent-free synthesis of valuable monofluoroalkenes was developed under ball-milling agitation. The use of 1.0 equivalent of carbonyl substrates and 1.1 equivalent of fluorophosphonoacetate derivatives with a weak inorganic base enabled the formation of the desired products after 30 min of reaction under sustainable conditions with minimized synthetic waste. No sequential addition of base, fluorophosphonate, and carbonyl substrates was needed, and the desired products were obtained with high purity only after a simple filtration. The protocol showed general efficiency and tolerance to a large panel of carbonyl substrates including aldehydes and ketones, as well as fluorophosphonoacetate derivatives with moderate stereoselectivities and yields ranging from 21 % to 99 % (48 examples).