Deoxygenation of Sulfoxides to Sulfides with Thionyl Chloride and Triphenylphosphine: Competition with the Pummerer Reaction

Abstract

Although a number of methods have been developed to reduce sulfoxides to sulfides, many of these processes are limited by side reactions, low yields, poorly available reagents, or harsh reaction conditions. We recently studied the reaction of various sulfoxides with SOCl2 and Ph3P. We were able to obtain the corresponding sulfides in excellent yields (>90%) when aliphatic and aromatic sulfoxides were treated with SOCl2 as a catalyst and Ph3P in THF at room temperature.

I2/K2S2O8: An Unprecedented Deoxygenating System for N‐Oxides and Sulfoxides

“…Other reagents such as sulfur reagents, phosphorus reagents, were also used for deoxygenation. On other side, different catalytic systems have been employed for the deoxygenation of sulfoxide viz., B(C 6 F 5 ) 3 /hydrosilanes, I 2 , Zn(OTf) 2 /boranes, ruthenium nanoparticles, silane/MoO 2 Cl 2 , oxo complexes, gold nanoparticles, SOCl 2 , and Fe powder, etc.…”

B(C6F5)3‐Catalyzed Deoxygenation of Sulfoxides and Amine N‐Oxides with Hydrosilanes

“…[5] The past decade has witnessed spectacular advances in metal-free catalytic reductions, particularly with the use of B(C 6 F 5 ) 3 /silanes. Over the past years, many systems have been employed for the deoxygenation of sulfoxides, including reagents such as silane/MoO 2 Cl 2 , [6] oxo complexes, [7] gold nanoparticles, [8] zinc(II) trifluoromethanesulfonate/bis(pinacolato)diboron [Zn(OTf ) 2 /B 2 (pin) 2 ] or Zn(OTf ) 2 /boranes, [9] SOCl 2 , [10] Fe powder, [11] ruthenium nanoparticles, [12] and I 2 . Over the past years, many systems have been employed for the deoxygenation of sulfoxides, including reagents such as silane/MoO 2 Cl 2 , [6] oxo complexes, [7] gold nanoparticles, [8] zinc(II) trifluoromethanesulfonate/bis(pinacolato)diboron [Zn(OTf ) 2 /B 2 (pin) 2 ] or Zn(OTf ) 2 /boranes, [9] SOCl 2 , [10] Fe powder, [11] ruthenium nanoparticles, [12] and I 2 .…”

“…Consequently, the combined use of B(C 6 F 5 ) 3 and hydrosilanes allows the deoxygenation of alcohols [3] and ethers [4] as well as carbonyl compounds and their derivatives. Over the past years, many systems have been employed for the deoxygenation of sulfoxides, including reagents such as silane/MoO 2 Cl 2 , [6] oxo complexes, [7] gold nanoparticles, [8] zinc(II) trifluoromethanesulfonate/bis(pinacolato)diboron [Zn(OTf ) 2 /B 2 (pin) 2 ] or Zn(OTf ) 2 /boranes, [9] SOCl 2 , [10] Fe powder, [11] ruthenium nanoparticles, [12] and I 2 . [2] In addition, the reduction of sulfoxides and amine N-oxides into their corresponding sulfides and amines is an important reaction owing to its considerable utility in organic synthesis.…”

Phosphine functionalized polyphosphazenes: soluble and re-usable polymeric reagents for highly efficient halogenations under Appel conditions

“…They are employed as reagents [2][3][4], as complex-ligands for transition-metal catalysts or act as organo-catalysts [5][6][7]. The use of phosphines as reagents, in particular triphenylphosphine, enables a vast number of synthetic transformations including Appel-type halogenations [8], Staudinger [9], Mitsunobu [10][11][12], and Wittig reactions [13,14], as well as amidations [15] and the reduction of sulfonyl chlorides and sulfoxides to thiols and sulfides [16,17]. Although this wide variety of possible applications make phosphine reagents a valuable tool for the synthetic organic chemist, all of these examples suffer from two major drawbacks.…”