Direct Electrochemical Selenylation/Cyclization of Alkenes: Access to Functionalized Benzheterocycles

Abstract

A catalyst-free, environmentally friendly, and efficient electrochemical selenylation/cyclization of alkenes has been developed with moderate to excellent yields. This selenylated transformation proceeds smoothly and tolerates a wide range of synthetically useful groups to deliver diverse functionalized benzheterocycles, including iminoisobenzofuran, lactones, oxindoles, and quinolinones. Moreover, the present synthetic route could also be readily scaled up to gram quantity with convenient operation in an undivided cell.

Cobalt-Catalyzed Cyclization of UnsaturatedN-Acyl Sulfonamides: a Diverted Mukaiyama Hydration Reaction

“…Cycloisomerizations of alkenyl N -acyl sulfonamides to N -sulfonyl lactams have been described, mediated by Ph 3 PAuCl, Ir catalysts, NbCl 5 , and Zn­(OTf) 2 /TfOH (Figure A). Cyclic N -sulfonyl imidates have generally been accessed through electrophilic cyclization of N -acyl sulfonyl alkenes mediated by iodine, m -CPBA, Ph 2 Se 2 , or TsN 3 . ,, The direct cycloisomerization of alkenyl N -acyl sulfonamides to furnish cyclic N -sulfonyl imidates is unknown. , …”

Selenium‐Electrocatalytic Cyclization of 2‐Vinylanilides towards Indoles of Peptide Labeling

“…[15] Recently, our group has been focusing on the synthesis of selenium compounds by electrochemical strategy. [16] With our continued efforts in electrochemically driven cyclic reactions, [17] we report herein a selenaelectro-catalyzed dehydrogenative cyclization of 2-vinylanilides for the synthesis of indoles via CÀ H/NÀ H activation. Notable features of our general strategy include 1) exceedingly mild and environmental-friendly reaction conditions in a transition metal-and chemical oxidantfree fashion, 2) an unparalleled broad substrate scope with sensitive functional group tolerance, 3) a recyclable selenium catalysis manifold with easy scale-up in flow chemistry, and 4) robust dehydrogenative cyclization for the late-stage modification of complex bioactive molecular system, thereby 5) setting the stage for versatile syntheses of decorated indoles with peptide labeling [18] (Scheme 1c).…”

Direct Electrooxidative Selenylation/Cyclization of Alkynes: Access to Functionalized Benzo[b]furans

“…Recently, several electrochemically induced radical functionalizations of alkynes have been reported [ 43 , 44 , 45 , 46 ]. Inspired by the recent developments in the area of electrochemical selenylation and our continuous research interest in the electrochemical synthesis [ 47 , 48 , 49 , 50 , 51 ], herein, we developed an electrochemical selenylation/cyclization method of alkynes for the synthesis of 3-selenylated benzofuran motifs with wide functional groups under mild electrochemical anodic oxidation conditions in an undivided cell ( Scheme 1 c).…”