Alkyl Sulfonyl Fluorides as Ambiphiles in the Stereoselective, Palladium(II)-Catalyzed Cyclopropanation of Unactivated Alkenes

The ambiphilic reactivity of alkyl sulfonyl fluorides in the stereoselective synthesis of diverse cyclopropanes from ole-fins under palladium(II) catalysis is presented. The sulfonyl fluoride functionality serves as both an acidifying group and an internal oxidant within the ambiphile, enabling the successive carbopalladation and oxidative addition steps in the catalytic cycle, respectively. The transformation grants access to cis-substituted cyclopropanes and exhibits broad compatibility with various alkyl sulfonyl fluorides, including those bearing –CN, –CO2R, isoxazolyl, pyrazolyl, and aryl groups. With internal alkene substrates, 1,2-3-trisubstituted cyclopropanes that are otherwise challenging to synthesize are formed in good to moderate yield and predictable diastereoselectivity. Detailed mechanistic insights from reaction progress kinetic analysis (RPKA) and density functional theory (DFT) calculations reveal that the SN2-type C–SO2F oxidative addition is the turnover-limiting and diastereoselectivity-determining step.