A novel synthetic route to ethyl 3-substituted-trans-2,3-difluoro-2-acrylates and their reactions with nucleophiles

Reaction of a variety of trans-1-trimethylsilyl-1,2-difluoroalkenes with ethyl chloroformate in the presence of potassium fluoride gave the corresponding ethyl 3-substituted-trans-2,3-difluoro-2-acrylates in good yields, which reacted with a variety of nucleophiles such as hydrazine hydrate, amidines and thiourea etc. in the presence of bases to afford the corresponding 4-fluoropyrazole, 5-fluoropyrimidine and 5-fluoro-2-uracil derivatives in good yields.