Rapid transformation of sulfinate salts into sulfonates promoted by a hypervalent iodine(III) reagent

Abstract

An alternative method for forming sulfonates through hypervalent iodine(III) reagent-mediated oxidation of sodium sulfinates has been developed. This transformation involves trapping reactive sulfonium species using alcohols. With additional optimization of the reaction conditions, the method appears extendable to other nucleophiles such as electron-rich aromatic systems or cyclic ethers through a ring opening pathway.

Activation of O-Electrophiles via Structural and Solvent Effects: SN2@O Reaction of Cyclic Diacyl Peroxides with Enol Acetates

“…The addition of p -TsOH·H 2 O (entry 3) led to a low (28%) yield of 3a . Increasing the reaction temperature in THF did not improve the yield of 3a (entry 4), possibly due to the cleavage of THF in the presence of the electrophile and p -TsOH·H 2 O. − The 33% yield of 3a was obtained in the case of CH 3 CN as the solvent (entry 5). However, the yield of 3a increased after switching from catalytic amounts of acid to acidic solvents such as acetic acid and trifluoroethanol (entries 6 and 7).…”

Iron(III)-Mediated Oxysulfonylation of Enamides with Sodium and Lithium Sulfinates

“…However, no trapping products such as 15 , a common product in reactions involving sulfonyl radicals, could be detected via 1 H NMR or MS. Interestingly, the reaction of sulfinate salt 2a with Fe­(NO 3 ) 3 ·9H 2 O in MeOH in the absence of an enamide afforded the sulfonic acid ester 16 in 62% yield (Scheme b). Such products are typically formed from highly electrophilic, cationic sulfonyl species . As the incorporation of MeOH into the final product of type 4 could also occur in a secondary acid-catalyzed addition to an initially formed amidovinylsulfone, we treated vinyl sulfone 3a with MeOH in the presence of 2 equiv of Fe­(NO 3 ) 3 ·9H 2 O.…”

“…Such products are typically formed from highly electrophilic, cationic sulfonyl species. 32 As the incorporation of MeOH into the final product of type 4 could also occur in a secondary acid-catalyzed addition to an initially formed amidovinyl sulfone, we treated vinyl sulfone 3a with MeOH in the presence of 2 equivalents of Fe(NO3)3•9 H2O. No product formation was observed in this case and the enamide could be recovered almost quantitatively after two hours.…”

Synthesis and applications of sodium sulfinates (RSO2Na): a powerful building block for the synthesis of organosulfur compounds

“…Hypervalent iodine-promoted O -sulfonylation of alkyl alcohols with sodium sulfinates was developed by the Canesi group. 371 A series of alkyl sulfonate esters were obtained in moderate to good yields using various functionalized primary and secondary alcohols with 2-methylbenzenesulfinate in the presence of (diacetoxyiodo)benzene (PIDA) as described in Scheme 263 . Disappointingly, sterically hindered tertiary alcohols, such as tert -butanol, were unsuccessful.…”