5-Arylthianthreniumyl Perchlorates as a Benzyne Precursor

Addition of thianthrene cation radical to non-conjugated dienes—Part I: Addition to one double bond

“…Numerous reactions of the thianthrene cation radical with nucleophiles, electron-rich aromatics, alcohols, azoalkanes, organometallics, ketones, and various derivatives of aldehydes and ketones are to be found, and have been in part reviewed, in the literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Among these reactions, additions to alkenes and cycloalkenes, which were first discovered more than 20 years ago [15,16], have drawn, recently, further extensive interest [17][18][19][20].…”

Transition‐Metal‐Free N‐Arylation of Amines by Triarylsulfonium Triflates

“…Recently, the Pd‐catalyzed arylation of arylboronic acids, alkenes, and alkynes using [Ar 3 S][OTf], the visible‐light photocatalytic reduction and radical addition of [Ar 3 S]X to alkenes, and the transition‐metal‐free aromatic ipso ‐substitution of [Ar 3 S][OTf] with [ 18 F]fluorides have evidenced their great usefulness in the C−C and C−F bond formation reactions . Although the transition‐metal‐free reactions of primary anilines and secondary aliphatic amines with diaryliodonium salts under alkaline conditions have been reported to produce various arylamines by nucleophilic aromatic substitution, aryne intermediates, or ligand exchange/reductive elimination processes,– the interactions between triarylsulfonium salts and amines or their derivatives are rarely known . As a class of alternative and emerging aryl‐transfer sources, triarylsulfonium salts have featured several advantages such as non‐volatility, easy preparation, non‐toxicity, moderate reactivity, and broad structural diversity.…”

“…[9,10] Although the transition-metal-free reactions of primary anilines and secondary aliphaticamineswith diaryliodonium salts under alkaline conditions have been reported to produce variousa rylamines by nucleophilic aromatic substitution, aryne intermediates,o rl igand exchange/reductivee limination processes, [7a-d] the interactions between triarylsulfonium salts and amines or their derivativesa re rarely known. [11] As ac lass of alternative and emerging aryl-transfer sources, triarylsulfonium salts have featured several advantages such as non-volatility,e asyp reparation, non-toxicity,m oderate reactivity,a nd broads tructural diversity.I mportantly,t he thermalg ravimetric analysiss howedt hat triphenylsulfonium triflate ([Ph 3 S][OTf]) has am uch higher onset decomposition temperature (405.8 8C) than diphenyliodonium triflate ([Ph 2 I][OTf], 207.0 8C) (see the Supporting Information), hinting at much better thermal stability of the former than the latter.N evertheless,a pplicationo ft he advantageous triarylsulfonium salts as arylation reagents is to dates ignificantlyu nderdeveloped compared to the corresponding diaryliodonium salts. [4a, 6-8] As ac ontinuation of our interest in the use of triarylsulfonium salts for arylation, [8a, 9] we first tested the reactions of [Ph 3 S] [OTf] with different types of amines under transition-metal-free conditions.…”

“…tBuONa, CsOH, KOH, and NaOH were moderately effective, affording 3a in lower yields. Reaction of 1a and 2a with lithium diisopropylamide (LDA) or nBuLi (at À78 8Ct or oomt emperature or at reflux in THF) [11] gave 7-12 %o f3a.I ts hould be noted that, in most reactions,asmall amount of N-cyclohexyl-N-phenylaniline (4a)w as formed accompanied with 3a,b ut it could be easily removed by column chromatography.O ther bases such as K 2 CO 3 ,K F, DBU, and NEt 3 were completelyi nert at 80 8C, thus 3a was not formed. Moreover,i ft he reactiono f1a and 2a was run at 80 8Ci nt he absence of base, no desired N-phenylationp roduct was obtained.…”

Synthesis of 2-(arylthio)-3'-(alkyl- or dialkylamino)diphenyl sulfides via 5-arylthianthrenium perchlorates and their complexations with silver(I) and lead(II) ions

“…Interestingly, heating a mixture of 2 and NaSH·xH 2 O in either PhH/H 2 O (1 : 1, v/v) or THF/H 2 O (10 : 1, v/v) at reflux resulted in the formation of 2,2'-bis[2-(arylthio)phenylthio]diphenyl sulfides 6. Recently, we reported that compounds 2 (X = MeO, Y = H) reacted with diethylamine in the presence of LDA in THF at reflux to give 2-(4-anisylthio)-3'-(diethylamino)diphenyl sulfide (7a) (57%) and 2-(4-anisylthio)-2'-(diethylamino)diphenyl sulfide (8a) (11%) together with thianthrene (9) (8%) 8 (Scheme 1).…”