Mono- and Difluoromethylation of 3(2H)-Pyridazinones.

A method for direct N-monofluoromethylation of pyridazinones with S-monofluoromethyl-S-phenyl-2,3,4,5-tetramethylphenylsulfonium triflate is disclosed. A method for the N- and O-difluoromethylated pyridazinones with TMSCF2Br as the only promising difluorocarbene precursor is also reported. Substrates with various relevant functional groups, including analogues of Lynparza, are tolerated under both methods.

Selective Csp3-F Bond Functionalization with Lithium Iodide.

A highly efficient method for C-F bond functionalization of a broad variety of activated and unactivated aliphatic substrates with inexpensive lithium iodide is presented. Primary, secondary, tertiary, benzylic, propargylic and α-functionalized alkyl fluorides react in chlorinated or aromatic solvents at room temperature or upon heating to the corresponding iodides which are isolated in 91-99% yield. The reaction is selective for aliphatic monofluorides and can be coupled with in situ nucleophilic iodide replacements to install carbon-carbon, carbon-nitrogen and carbon-sulfur bonds with high yields. Alkyl difluorides, trifluorides, even in activated benzylic positions, are inert under the same conditions and aryl fluoride bonds are also tolerated.