A sulfite ester (also known as an organosulfite) is a

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ...

with the structure (RO)(R'O)SO. They adopt a

trigonal pyramidal molecular geometry In chemistry, a trigonal pyramid is a molecular geometry with one atom at the apex and three atoms at the corners of a trigonal base, resembling a tetrahedron (not to be confused with the tetrahedral geometry). When all three atoms at the corners ...

due to the presence of

lone pairs In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bondIUPAC ''Gold Book'' definition''lone (electron) pair''/ref> and is sometimes called an unshared pair or non-bonding pair. Lone ...

on the sulphur atom. When substituents R and R' differ, the compound 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 ...

owing to the stereogenic sulphur centre; when the R groups are the same the compound will have idealised C_s

molecular symmetry Molecular symmetry in chemistry describes the symmetry present in molecules and the classification of these molecules according to their symmetry. Molecular symmetry is a fundamental concept in chemistry, as it can be used to predict or explain m ...

. They are commonly prepared by the reaction of

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 ...

with alcohols. The reaction is typically performed at room temperature to prevent the alcohol being converted into a

chloroalkane An organochloride, organochlorine compound, chlorocarbon, or chlorinated hydrocarbon is an organic compound containing at least one covalently bonded atom of chlorine. The chloroalkane class (alkanes with one or more hydrogens substituted by chlor ...

. Bases such as

pyridine Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a d ...

can also be used to promote the reaction: : 2 ROH + SOCl₂ → (RO)₂SO + 2

HCl HCL may refer to: Science and medicine * Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia * Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development * Hollow-cathode lamp, a spe ...

The pesticide

endosulfan Endosulfan is an off-patent organochlorine insecticide and acaricide that is being phased out globally. It became a highly controversial agrichemical due to its acute toxicity, potential for bioaccumulation, and role as an endocrine disruptor. ...

is a sulfite ester. Some simple members include ethylene sulfite,

dimethyl sulfite Dimethyl sulfite is a sulfite ester with the chemical formula (CH3O)2SO. Dimethyl sulfite is used as an additive in some polymers to prevent oxidation. It is also a potentially useful high energy battery electrolyte solvent. Structure and confo ...

, and diphenylsulfite. Many examples have been prepared from diols, such as sugars. Sulfite esters can be powerful

alkylation Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting ...

and hydroxyalkylation reagents.

References

{{Functional Groups Functional groups *