Reagent-controlled
regiodivergent ring-opening reactions of trichloromethylcyclopropane
carboxylates have been developed. The regioselectivity of bond cleavage
is completely controlled by the proper choice of silver salts; the
treatment of trichloromethylcyclopropane with AgBF4 led
to C2–C3 bond cleavage and fluorination to afford fluorinated
β,γ-unsaturated ester with high stereoselectivity, while
the reaction with AgOAc in THF gave a γ,δ-unsaturated
ester through the reductive cleavage of the C1–C2 bond.