The synthesis of fluoroheterocyclic ketene aminals

The synthesis of fluoroheterocyclic ketene aminals was investigated. Fluorobenzyl ketene dithioacetals Ic reacted with nitric acid in the presence of concentrated sulfuric acid to give compound 2c. 1 reacted with diamines to afford 3-4. C-fluorobenzylation of 3-4 give the corresponding 5-8.