General Synthesis of Alkenyl Sulfides by Palladium-Catalyzed Thioetherification of Alkenyl Halides and Tosylates

Abstract

The cross-coupling reaction of alkenyl bromides with thiols catalyzed by palladium complexes derived from inexpensive dppf ligand is reported. These reactions occur under low catalyst loading and in high yields and display wide scope, including the coupling of bulky thiols and trisubstituted bromoolefins, and functional group tolerance. In addition, the thioetherification of less reactive chloroalkenes and, for the first time, alkenyl tosylates was accomplished using a catalyst generated from CyPF tBu alkylbisphosphine ligand.

Unconventional Reactivity of Ethynylbenziodoxolone Reagents and Thiols: Scope and Mechanism

“…These observations are consistent with the intermediacy of vinylbenziodoxolones en route to the final 1,2-dithio-1-alkene products.A dditionally,t he reactions of thiols with vinylbenziodoxolones provide ac onveniententry to vinyl sulfides, which are usually prepared by transition metal catalyzed cross-coupling reactions. [19] Conversion of vinylbenziodoxolone 7 to the 1,2-dithio-1alkene product was probed experimentally and computationally.S everale xperimental observations support the hypothesis that this second CÀSb ond-forming event involves at hiyl radical rather than at hiolate. Substoichiometric amounts of the free-radical initiator 2,2'-azobis(2-methylpropionitrile) (AIBN) were found to promote product formation (Figure 4a).…”

Electrochemical Oxidation Cross Dehydrogenative Coupling of Enamines and Thiophenols for the Synthesis of Vinyl Sulfides

“…Over the past decades, the construction of vinyl sulfide motifs has received considerable attention, [2] and subsequently the C−H/S−H cross coupling [3] has emerged as a more privileged approach to the formation of C−S bond. However, harsh reaction conditions, [2c,f,h–l,3b,e] such as the addition of external oxidants and catalysts, as well as the environmental pollution and atomic economy issues have severely restricted the synthesis of vinyl sulfides. Therefore, developing more efficient, green, and atomic economy methods for the preparation of organic sulfides continue to be highly attractive.…”

Catalytic conversion of alkynes to α-vinyl sulfides mediated by carbene-linker-carbene (CXC) rhodium and iridium complexes

“…[1][2][3][4] They are present in biologically active compounds and pharmaceuticals, and found application in materials science and total synthesis. [5][6][7] Thus, the development of atomeconomical methods for the preparation of alkenyl sulfides such as the catalysed intermolecular functionalisation of alkynes (see Scheme 1, a) has been attracting much interest in recent years.…”

“…[8][9][10] Not surprisingly, the use of transition metal catalysis provides substantial tunable control of the regioselectivity outcomes. 5 Rhodium catalysts are of particular interest. These species are often referred to as "chameleonic species" 8,11 because subtle modifications of the ancillary ligands significantly affect their activity and selectivity towards the Markovnikov (α-vinyl sulfides) or the anti-Markovnikov (E/Z-β-vinyl sulfides) addition products.…”

“…These species are often referred to as "chameleonic species" 8,11 because subtle modifications of the ancillary ligands significantly affect their activity and selectivity towards the Markovnikov (α-vinyl sulfides) or the anti-Markovnikov (E/Z-β-vinyl sulfides) addition products. 5,8,[12][13][14][15] The most generally accepted mechanism involves the oxidative addition of the thiol S-H bond to the Rh(I) metal precursor to generate the corresponding Rh(III) intermediate as a first step (Scheme 1, b). 8,11 Then, the 1,2or 2,1-alkyne insertion into the Rh-S or Rh-H bonds takes place to produce four possible reaction paths.…”