Synthesis of Perfluoroalkyl-Substituted γ-Lactones and 4,5-Dihydropyridazin-3(2 H)-ones via DonorAcceptor Cyclopropanes.

Rh2(OAc)4-Catalyzed decomposition of diazo esters in the presence of perfluoroalkyl- or perfluoroaryl-substituted silyl enol ethers smoothly provided the corresponding alkyl 2-siloxycyclopropanecarboxylates in very good yields. The generated donoracceptor cyclopropanes are equivalents of γ-oxo esters, which we demonstrated by their one-pot transformations to yield fluorine-containing heterocycles. A reductive procedure selectively afforded perfluoroalkyl-substituted γ-hydroxy esters or γ-lactones. The treatment of the donoracceptor cyclopropanes with hydrazine or phenylhydrazine afforded a series of perfluoroalkyl- and perfluoroaryl-substituted 4,5-dihydropyridazin-3(2 H)-ones. [ABSTRACT FROM AUTHOR]