Preparation of Alkyl Di(p-tolyl)sulfonium Salts and Their Application in Metal-Free C(sp³)–C(sp³) and C(sp³)–C(sp²) Bond Formations

Abstract

Alkyldiarylsulfonium salts were synthesized by a combination of active sulfonium species, prepared through the activation of diarylsulfoxide, and alkyl nucleophiles. The isolated sulfonium salts were subjected to the allylation and cyclopropanation of the active methylene compounds and metal-free C(sp3)–C(sp2) couplings via oxyallyl cation intermediates under mild conditions. The series of reactions included an umpolung strategy for the coupling of alkyl nucleophiles and metal-free C–C bond formation using sulfonium salts.

Photogenerated donor–donor diazo compounds enable facile access to spirocyclopropanes

“…Most importantly, this includes the Simmons-Smith reaction, transition-metal mediated carbene transfer, ylide addition, Michael-initiated ring closure, and organocatalytic methods. [8][9][10][11][12][13] One of the earliest and simplest methods discovered is the thermal 14 or photo 15,16 induced extrusion of nitrogen from D 1 -pyrazoline structures, which can be generated by (3+2)-cycloaddition of diazo compounds to alkenes. 17 Historically, direct addition of diazo compounds was limited to either diazomethane or a-stabilized motifs such as diazo acetates.…”