Search

The one‐pot synthesis of λ4‐dibenzothiophen‐5‐imino‐N‐dibenzothiophenium triflate (1) in multigram scale is reported. This compound reacts with Rh2(esp)2 (esp=α,α,α′,α′‐tetramethyl‐1,3‐benzenedipropionic acid) generating a Rh‐coordinated sulfonitrene species, which is able to transfer the electrophilic nitrene moiety to olefins. When indenes are used as substrates, isoquinolines are obtained in good yields. We assumed that after formation of the corresponding N‐sulfonio aziridine, a ring expansion occurs via selective C−C bond cleavage and concomitant elimination of dibenzothiophene. Unexpectedly, a similar protocol transforms 1‐arylcyclobutenes into 1‐cyano‐1‐arylcyclopropanes. Our calculations indicate that aziridination is not favored in this case; instead, sulfilimine‐substituted cyclobutyl carbocations are initially formed, and these evolve to the isolated cyclopropanes via ring contraction. Both procedures are operationally simple, tolerate a range of functional groups, including oxidation‐sensitive alcohols and aldehydes, and enable the convenient preparation of valuable 15N‐labelled products. These results demonstrate the potential of 1 to provide alternative pathways for the selective transfer of N‐atoms in organic molecules. [ABSTRACT FROM AUTHOR]

This manuscript reports the synthesis and structure of an unprecedented sulfonium salt, 5‐(trifluorovinyl)dibenzothiophenium triflate, and its use as a versatile reagent for the introduction of the bioisosteric 1,1,2‐trifluoroethylene linker in drug‐like structures. The protocol developed consists of the reaction of this compound with alcohols and phenols to deliver a complete set of 1,2,2‐trifluoro‐2‐(alkoxy‐/aryloxy)ethyl sulfonium salts, which have been purified by column chromatography and fully characterized. Subsequent single electron reduction under mild photochemical conditions efficiently affords the corresponding fluoroalkyl radicals that are trapped either intra‐ or intermolecularly through their reaction with (hetero)arenes. Theoretical calculations are used to evaluate the conformational consequences derived from the presence of the CF2−CHF tether. [ABSTRACT FROM AUTHOR]