Methyl fluorosulfonate, also known as magic methyl, is the

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

with the formula FSO₂OCH₃. It is a colorless liquid that is used as a strong

methylating agent In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These t ...

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

. Because of its extreme toxicity, it has largely been replaced by the related reagent

methyl trifluoromethanesulfonate Methyl trifluoromethanesulfonate, also commonly called methyl triflate and abbreviated MeOTf, is the organic compound with the formula CF3SO2OCH3. It is a colourless liquid which finds use in organic chemistry as a powerful methylating agent. T ...

Synthesis and reactions

It is prepared by distillation of an equimolar mixture of

fluorosulfonic acid Fluorosulfuric acid (IUPAC name: sulfurofluoridic acid) is the inorganic compound with the chemical formula HSO3F. It is one of the strongest acids commercially available. It is a tetrahedral molecule and is closely related to sulfuric acid, H2SO4 ...

and

dimethyl sulfate Dimethyl sulfate (DMS) is a chemical compound with formula (CH3O)2SO2. As the diester of methanol and sulfuric acid, its formula is often written as ( CH3)2 SO4 or Me2SO4, where CH3 or Me is methyl. Me2SO4 is mainly used as a methylating agent ...

. It was originally produced by the reaction of

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

with

. Methyl fluorosulfonate is a highly electrophilic reagent for

methylation In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These t ...

. It is ranked as less powerful than methyl trifluoromethanesulfonate.

Toxicity

Similar to

phosgene Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, espe ...

, it is acutely toxic by inhalation, with an LC₅₀ (rat, 1 hour) of about 5 ppm. Several cases of poisoning resulting in death from

pulmonary edema Pulmonary edema, also known as pulmonary congestion, is excessive edema, liquid accumulation in the parenchyma, tissue and pulmonary alveolus, air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia an ...

have been reported.{{cite journal , author = Hite, M. , author2=Rinehart, W. , author3=Braun, W. , author4=Peck, H. , year = 1979 , title = Acute toxicity of methyl fluorosulfonate (Magic Methyl) , journal = AIHA Journal , volume = 40 , issue = 7 , pages = 600–603 , pmid = 484483 , doi = 10.1080/00028897708984416

References

Methylating agents Methyl esters Sulfonate esters