Sodium methylsulfinylmethylide explained

Sodium methylsulfinylmethylide (also called NaDMSO or dimsyl sodium) is the sodium salt of the conjugate base of dimethyl sulfoxide. This unusual salt has some uses in organic chemistry as a base and nucleophile.

Since the first publication in 1965 by Corey et al.,^[1] a number of additional uses for this reagent have been identified.^[2]

Preparation

Sodium methylsulfinylmethylide is prepared by heating sodium hydride or sodium amide^[3] in DMSO^[4]

CH₃SOCH₃ + NaH → CH₃SOCH₂^-Na⁺ + H₂

CH₃SOCH₃ + NaNH₂ → CH₃SOCH₂^-Na⁺ + NH₃

Reactions

As a base

The pK_a of DMSO is 35, which leads NaDMSO to be a powerful Brønsted base. NaDMSO is used in the generation of phosphorus and sulfur ylides.^[5] NaDMSO in DMSO is especially convenient in the generation of dimethyloxosulfonium methylide and dimethylsulfonium methylide.^[6]

Reaction with esters

NaDMSO condenses with esters (1) to form β-ketosulfoxides (2), which can be useful intermediates.^[7] Reduction of β-ketosulfoxides with aluminium amalgam gives methyl ketones (3).^[8] Reaction with alkyl halides followed by elimination gives α,β-unsaturated ketones (4). β-ketosulfoxides can also be used in the Pummerer rearrangement to introduce nucleophiles alpha to a carbonyl (5).^[9]

External links

• Web site: . The Dimethyl Sulfoxide (DMSO) Anion — Dimsyl Ion . October 2007 . https://web.archive.org/web/20110711080250/http://www.gaylordchemical.com/bulletins/bulletin110b/Bulletin110B.pdf . 2011-07-11.
• Web site: Preparation of dimsyl sodium . June 2009.

Notes and References

1. . 1965 . 87 . 1345–1353 . Methylsulfinyl Carbanion (CH₃-SO-CH₂^-). Formation and Applications to Organic Synthesis . 10.1021/ja01084a033 . Corey, E. J. . Chaykovsky, M. . Elias James Corey . 6.
2. Mukulesh Mondal "Sodium methylsulfinylmethylide: A versatile reagent" Synlett 2005, vol. 17, 2697-2698.
3. . 1973 . 59 . 53–64 . 10.1016/S0022-328X(00)95020-4 . Preparation and reactions of the mono- and dialkali salts of dimethyl sulfone, dimethyl sulfoxide, and related compounds . Kaiser, E. M. . Beard, R. D. . Hauser, C. R..
4. Web site: Preparation of dimsyl sodium.
5. An asymmetric route to enantiomerically pure 1,2,3-trisubstituted cyclopropanes . . 1992 . 57 . 6265–6270 . 10.1021/jo00049a038 . Romo, D. . Myers, A. I. . 23.
6. Book: Trost, B. M.

   Melvin, L. S., Jr.

   . Sulfur Ylides: Emerging Synthetic Intermediates . . New York . 1975 . 0-12-701060-2.
7. One-pot synthesis of β-keto sulfones and β-keto sulfoxides from carboxylic acids . . 1989 . 54 . 5620–5623 . 10.1021/jo00284a043 . Ibarra, C. A . Rodgríguez, R. C . Monreal, M. C. F . Navarro, F. J. G. . Tesoreo, J. M. . 23.
8. 1,4-Dipole-metalated quinone strategy to (±)-4-demethoxydaunomycinone and (±)-daunomycinone. Annelation of benzocyclobutenedione monoketals with lithioquinone bisketals . . 1981 . 46 . 4825–4836 . 10.1021/jo00337a002 . Swenton, J. S. . Anderson, D. K. . Jackson, D. K. . Narasimhan, L. . 24.
9. . 1985 . 643–645 . Isibashi, H. . Okada, M.. Komatsu, H. . Ikeda, M. S. . 10.1055/s-1985-31290 . 1985 . A New Synthesis of Substituted Cyclopentenones by Olefin Cyclization Initiated by Pummerer Reaction Intermediates. 6/7 . 95643470 .