Interaction of Fluoroxenonium Triflate, Fluorosulfate, and Nitrate with Alkenes. Stereochemical Evidence for the Electrophilic Noble Gas Cation Addition to the Carbon-Carbon Double Bond

Article abstract of DOI:10.1021/jo00004a015

Reactions of fluoroxenonium triflate (1), fluorosulfate (2), and nitrate (3), prepared from XeF3 and the corresponding acids in CH2Cl2 at -50 deg C, with cyclohexene and 1-hexene result in β-fluoroalkyl triflates, fluorosulfates, and nitrates.Triflate 1 reacts with cyclohexene with exclusive formation of the cis isomer 4, the analogous reactions of fluorosulfate 2 and nitrate 3 give mixtures of the corresponding cis and trans isomers.Reactions of 1-hexene with reagents 1-3 lead to mixtures of two regioisomers with domination of the Markovnikov type of addition.The stereochemical result of these reactions is rationalized in terms of an electrophilic attack by the positive xenonium ion on the ?-electrons of the double bond with intermediate formation of organoxenonium species in analogy with the behavior of the isoelectronic iodine(III) species.