Sodium methylsulfinylmethylide (also called NaDMSO or dimsyl sodium) is the sodium salt of the

conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a ...

dimethyl sulfoxide Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula ( CH3)2. This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds a ...

. This unusual salt has some uses in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; ...

as a base and

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

. Since the first publication in 1965 by

Corey Corey is a masculine given name and a surname. It is a masculine version of name Cora, which has Greek origins and is the maiden name of the goddess Persephone. The name also can have origins from the Gaelic word ''coire'', which means "in a caul ...

''et al.'', a number of additional uses for this reagent have been identified.

Preparation

Sodium methylsulfinylmethylide is prepared by heating

sodium hydride Sodium hydride is the chemical compound with the empirical formula Na H. This alkali metal hydride is primarily used as a strong yet combustible base in organic synthesis. NaH is a saline (salt-like) hydride, composed of Na+ and H− ions, in co ...

sodium amide Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is whit ...

DMSO Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula ( CH3)2. This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds an ...

: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 Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

and

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

ylide An ylide or ylid () is a neutral dipolar molecule containing a formally negatively charged atom (usually a carbanion) directly attached to a heteroatom with a formal positive charge (usually nitrogen, phosphorus or sulfur), and in which both atoms h ...

s. NaDMSO in DMSO is especially convenient in the generation of dimethyloxosulfonium methylide and dimethylsulfonium methylide.

Reaction with esters

NaDMSO

condense Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to ...

s with

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s (1) to form β-ketosulfoxides (2), which can be useful intermediates. Reduction of β-ketosulfoxides with

aluminium amalgam Aluminium can form an amalgam in solution with mercury. Aluminium amalgam may be prepared by either grinding aluminium pellets or wire in mercury, or by allowing aluminium wire to react with a solution of mercury(II) chloride in water. This amalga ...

gives

methyl In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many ...

ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...

s (3). Reaction with alkyl halides followed by elimination gives α,β-unsaturated ketones (4). β-ketosulfoxides can also be used in the

Pummerer rearrangement The Pummerer rearrangement is an organic reaction whereby an alkyl sulfoxide rearranges to an α- acyloxy–thioether (mono thioacetal-ester) in the presence of acetic anhydride. The stoichiometry of the reaction is: :RS(O)CHR'2 + Ac2O → ...

to introduce

s alpha to a

carbonyl In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containing a ...

(5). :

References

External links

* * {{cite web , url = http://stenutz.eu/sop/sop401.html , title = Preparation of dimsyl sodium , date=June 2009 Reagents for organic chemistry Organosodium compounds