Sulfinyl halide have the general formula R−S(O)−X, where X is a halogen. They are intermediate in oxidation level between sulfenyl halides, R−S−X, and

sulfonyl halide In inorganic chemistry, sulfonyl halide groups occur when a sulfonyl () functional group is singly bonded to a halogen atom. They have the general formula , where X is a halogen. The stability of sulfonyl halides decreases in the order fluorides ...

s, R−SO₂−X. The best known examples are sulfinyl chlorides, thermolabile, moisture-sensitive compounds, which are useful intermediates for preparation of other sufinyl derivatives such as sulfinamides, sulfinates, sulfoxides, and thiosulfinates. Unlike the sulfur atom in

s and sulfenyl halides, the sulfur atom in sulfinyl halides is

chiral Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from i ...

, as shown for methanesulfinyl chloride.

Sulfinyl chlorides

Sulfinic acid chlorides, or sulfinyl chlorides, are sulfinyl halides with the general formula R−S(O)−Cl. Methanesulfinyl chloride, CH₃S(O)Cl, is prepared by chlorination of dimethyl disulfide to give CH₃SCl₃, which is treated with acetic anhydride. It is a straw-colored liquid. Toluenesulfinyl chloride is prepared by treating sodium tosylate with

thionyl chloride Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately per year bein ...

: Also a straw-colored liquid, it boils near 100 °C at 0.5 mm Hg. A general approach to the formation of sulfinyl chlorides is by reaction of the corresponding

thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

with sulfuryl chloride, ; in cases where the

sulfenyl chloride In organosulfur chemistry, a sulfenyl chloride is a functional group with the connectivity , where R is alkyl or aryl. Sulfenyl chlorides are reactive compounds that behave as sources of . They are used in the formation of and bonds. According ...

, RSCl, results instead, a trifluoroperacetic acid oxidation affords the desired product, as in the case of 2,2,2-trifluoro-1,1-diphenyl ethanethiol: Conversion of F3CCPh2SH to F3CCPh2SCl and on to F3CCPh2S(O)Cl

Conversion of F3CCPh2SH to F3CCPh2SCl and on to F3CCPh2S(O)Cl

Reactions

These compounds react readily with nucleophiles like water, alcohols, amines, thiols, and Grignard reagents. If the nucleophile is water the product is a sulfinic acid, if it is an alcohol the product is a sulfinic ester, if it is a primary or secondary amine the product is a sulfinamide, if it is a thiol the product is a thiosulfinate, while if it is a Grignard reagent the product is a

sulfoxide In organic chemistry, a sulfoxide, also called a sulphoxide, is an organosulfur compound containing a sulfinyl () functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. E ...

. Because of their reactivity and instability, alkanesulfinyl chlorides are generally used without purification immediately after their synthesis. Storage is not recommended since pressure develops within the container due to hydrogen chloride release. Treatment of alkanesulfinyl chlorides having α-hydrogens with tertiary amine bases gives thiocarbonyl ''S''-oxides (sulfines) as isolable compounds. Thus, treatment of ''n''-propanesulfinyl chloride with

triethylamine Triethylamine is the chemical compound with the formula N(CH2CH3)3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine or tetraethylammonium, for which TEA ...

gives ''syn''-propanethial-''S''-oxide, the

lachrymatory agent Tear gas, also known as a lachrymator agent or lachrymator (), sometimes colloquially known as "mace" after the early commercial aerosol, is a chemical weapon that stimulates the nerves of the lacrimal gland in the eye to produce tears. In ad ...

of the

onion An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the oni ...

. Treatment of methanesulfinyl chloride or ethane-1,2-bis-sulfinyl chloride, (prepared by oxidative chlorination of 1,2-ethanedithiol, HSCH₂CH₂SH), with a tertiary amine in the presence of the chiral

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, usi ...

-derived secondary alcohol diacetone-D-glucose affords optically pure sulfinate esters by a process of Dynamic kinetic resolution. Sulfinyl chlorides undergo Friedel–Crafts reactions with arenes giving

Sulfinyl fluorides, bromides, and iodides

Room temperature hydrolysis of CF₃SF₃ gives the sulfinyl fluoride CF₃S(O)F in a few hours in quantitative yield. Treatment of CF₃S(O)F with hydrogen bromide at −78 °C gives the sulfinyl bromide CF₃S(O)Br, which is unstable at room temperature and readily disproportionates. Sulfinyl iodides are apparently unknown compounds.

References

{{reflist Halides Organosulfur compounds