Iron(III) Chloride‐Mediated Regio‐ and Stereoselective Chlorosulfonylation of Alkynes and Alkenes with Sodium Sulfinates

Abstract

Thea tom-economic and one-pot regioand stereoselective addition of sodium arenesulfinates to either alkynes or alkenes can be achieved with an iron(III) chloride hexahydrate [FeCl 3 ·6 H 2 O] catalytic system to afford b-haloalkenyl and bchloroalkyl sulfones in moderate to good yields.Scheme4.Tr ansformation of b-haloalkenyl sulfones via Suzukic oupling.Scheme3.Apossible reaction mechanism.

Switching of Sulfonylation Selectivity by Nature of Solvent and Temperature: The Reaction of β‐Dicarbonyl Compounds with Sodium Sulfinates under the Action of Iron‐Based Oxidants

“…On the basis of the literature data, we proposed a mechanism for the reaction of oxidative sulfonylation of dicarbonyl compounds with sodium sulfinates under the action of Fe (III) salts (Scheme ). The process is triggered by the oxidation of sulfinate anion 2a under the action of Fe (III) into S‐centered radical A , which then reacts with the enol form of the starting dicarbonyl compound 1a′ , resulting in C‐centered radical B (path 1) . Oxidation of radical B with Fe(III) and H + elimination lead to 3aa product.…”

Oxidative Sulfonylation of Multiple Carbon‐Carbon bonds with Sulfonyl Hydrazides, Sulfinic Acids and their Salts

“…The developed process was also extended to styrenes and aliphatic terminal and cyclic alkenes: coresponding β-chlorosulfones were obtained in 54-90% yields. [54] In the first step of the process, sulfonyl radical A is formed from the starting sodium sulfinate 92 under the action of FeCl 3 • 6H 2 O. Iron (III) chloride also serves as the Lewis acid activating the triple bond of alkyne 91 through the formation of complex B.…”

“…In the case of diphenylacetylene and sodium trifluoromethanesulfinate, the desired products were not observed. The developed process was also extended to styrenes and aliphatic terminal and cyclic alkenes: coresponding β‐chlorosulfones were obtained in 54–90% yields [54] …”

Regio‐ and Stereoselective Chloro Sulfoximidations of Terminal Aryl Alkynes Enabled by Copper Catalysis and Visible Light

“…Based on these observations and considering the results from other studies, in particular those related to additions of sulfonyl radicals to alkynes [3][4][5][6][7][8] and visible light photocatalysis with copper complexes, [11] the mechanism depicted in Scheme 4 can be proposed.…”

“…[4,5] Also iron salts have been used for promoting such additions. [6] More recently, sulfonyl chloride additions to alkynes have been initiated by visible light photoredox catalysis. [7,8] An example is Han's work, who observed highly stereoselective trans additions affording (E)-β-chlorovinyl sulfones by using an iridium catalyst/blue light combination for the activation.…”