A Mn(OAc)3 mediated oxidative C(sp2)–H sulfonylation of enamides and encarbamates with sodium and lithium sulfinates is reported.

As ingle-component, air-stable nickel precatalyst can catalyzet he isomerization of allylamides for the synthesis of enamides.T he scope of the reactione ncompassesv arious substituted allylamides anda llylcarbamates as well as homoallylamides.T he reactionc an be performed on am ultigram-scale without specialized glove-box equipment or Schlenk techniques.Keywords: enamides; enecarbamates; homogeneous catalysis;i somerization;nickel catalysis Enamidesa nd enecarbamates are very useful synthetic intermediates for various transformations,s uch as cycloadditions,c ross-coupling reactions or asymmetric C À Cb ond formations (Scheme1). [1][2][3][4] Furthermore,e namidesa nd enecarbamatesa re valuable substrates for asymmetric hydrogenation reactions. [3,4] Besides these applications,t he enamide motif is often found in natural products,f or example,a spergillamides [5] and salicylihalamides [6] . Due to importance of these classeso fc ompounds, several protocols for theirp reparation have been reported.[1-4] Classical procedures,s uch as the acylation of imines or the condensation of amides and carbonyl compounds require harsh reactionc onditions and lead to the formation of considerable amounts of byproducts.[7] An attractivea lternative is the transition metal-catalyzed [8][9][10][11] or base-mediated [12] isomerization of readily available N-allylamides.R ecently,G ooßen and co-workersd eveloped as tereoselective synthesis of enamides based on ar uthenium-catalyzed direct addition of amides to terminala lkynes [13][14][15] . Foro ne of our current research projects,w ew ere looking for an operationally simple,s calable and effiScheme 1. Synthesis and applicationso fe namides.

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An iron-mediated vicinal difunctionalization of enamides and enecarbamates with sulfinic acid salts and alcohols is described. This reaction proceeds under mild conditions and furnishes the oxysulfonylated products in moderate to excellent yields. Moreover, the direct incorporation of sulfur dioxide into the sulfonylated products via organolithium chemistry has been achieved. The formed NO -acetals are competent acylimine precursors. Their utilization as building block for the synthesis of biologically relevant β-amidosulfones is described as well. Introduction: Molecules bearing sulfonyl-derived functional groups, such as sulfones or sulfonamides, play an important role in organic chemistry and are widely used in various fields. 1,2 Among the different classes of sulfonyl-derived functional groups, sulfones are of particular interest. They display intriguing chemical and physical properties as well as interesting biological activities. Sulfones, which are often considered as chemical chameleons 3 , are versatile building blocks in organic synthesis. The sulfone motif can be found in various molecules with different applications ranging from agrochemcials and functional materials to active pharmaceutical ingredients. 2-4 Traditional approaches for the construction of sulfones include Friedel-Crafts type reactions of arenes with sulfonyl chlorides 5 , the oxidation of sulfides and sulfoxides 6 , addition reactions of sulfonyl radicals to alkenes and alkynes 7 or the electrophilic trapping of sulfinic acid salts 8,9. In the last ten years novel approaches based on the direct incorporation of sulfur dioxide 10, 11 or the functionalization of C-H bonds 12,13 have emerged as attractive and more sustainable alternatives.