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Synthesis of sulfinates and sulfinic acids
Alkyl arenesulfinates and S-thiosulfinates are readily prepared in good yields by the reaction of sulfinic acids and alcohols or thiols, respectively, in the presence of lanthanide(III) triflates as catalysts.
J. Drabowicz, M. Kwiatkowska, P. Kiełbasiński, Synthesis, 2008, 3563-3546.
The reaction of p-toluenesulfinic acid with 1,1′-carbonyldiimidazole (CDI) provides sulfinylimidazoles. The process spontaneously releases carbon dioxide upon addition of CDI to the acid suggesting the rapid formation of the proposed reagent. A subsequent reaction with a series of alcohols (primary, secondary, and tertiary) affords the corresponding sulfinate alkyl esters in very good yields.
J. L. Shaw, B. J. Austermuehle, J. M. Witte, T. R. Dorsey, C. Delach, C. G. Hamaker, S. R. Hitchcock, Synthesis, 2021, 53, 2693-2701.
An electrochemical oxidative coupling of thiophenols and alcohols provides sulfinic esters in the presence of O2 (air) as the oxygen source smoothly at room temperature.
H. Zhou, J. Duan, D. Xie, J. Yang, B. Ma, G. Wang, C. Wu, X.-C. Wang, Synthesis, 2020, 52, 2705-2712.
A simple and efficient method for converting methyl sulfones to sulfinic acids involves alkylation with a benzylic halide, followed by in situ elimination of the resulting styrene in the presence of excess base to yield a sulfinic acid in a single reaction process.
D. R. Gauthier, Jr., N. Yoshikawa, Org. Lett., 2016, 18, 5994-5997.
Sulfoxides bearing a tert-butyl group can be activated using N-bromosuccinimide (NBS) under acidic conditions. Subsequent treatment with various nitrogen, carbon, or oxygen nucleophiles affords a wide range of sulfinic acid amides, new sulfoxides, and sulfinic acid esters.
J. Wei, Z. Sun, Org. Lett., 2015, 17, 5396-5399.
Heterocyclic thioethers and sulfones serve as readily available precursors for a convenient synthesis of α-chiral sulfinates. Treatment of the sulfinates with hydroxylamine sulfonate in aqueous solution provides α-C-chiral primary sulfonamides in good yield with retention of stereochemical purity.
M. G. Johson, M. W. Gribble Jr., J. B. Houze, N. A. Paras, Org. Lett., 2014, 16, 6248-6251.
A mild, late-stage conversion of primary sulfonamides to several other functional groups occurs via initial reductive deamination of sulfonamides to sulfinates via an NHC-catalyzed reaction of transiently formed N-sulfonylimines. This method tolerates common functional groups, as exemplified by the late-stage derivatization of several complex pharmaceutical compounds.
P. S. Fier, K. M. Maloney, J. Am. Chem. Soc., 2019, 141, 1441-1445.
Sulfinyl transfer agents based on cinchona alkaloids quinine and quinidine as chiral auxiliaries have been developed.
B. Z. Lu, F. Jin, Y. Zhang, X. Wu, S. A. Wald, C. H. Senanayake, Org. Lett., 2005, 7, 1465-1468.
An oxidation-free method provides sulfinic acids and sulfinate salts from easily prepared sulfone-substituted benzothiazole derivatives under mild reaction conditions. One-pot syntheses of sulfones and sulfonamides are also described.
J. J. Day, D. L. Neill, S. Xu, M. Xian, Org. Lett., 2017, 19, 3819-3822.