Camphorsulfonic acid

Camphorsulfonic acid, sometimes abbreviated CSA or 10-CSA is an organosulfur compound. Like typical sulfonic acids, it is a relatively strong acid that is a colorless solid at room temperature and is soluble in water and a wide variety of organic substances.

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Camphorsulfonic acid

Names
Preferred IUPAC name (7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonic acid
Other names Reychler's acid; 2-Oxobornane-10-sulfonic acid
Identifiers
CAS Number	5872-08-2 Y 35963-20-3 (1R) Y 3144-16-9 (1S) Y
3D model (JSmol)	Interactive image Interactive image
Beilstein Reference	2216194
ChEBI	CHEBI:55379 Y
ChemSpider	17438 Y 116050 (1R) Y 189449 (1S) Y 2318313 (4S) Y
ECHA InfoCard	100.025.024
EC Number	227-527-0
MeSH	10-Camphorsulfonic+acid
PubChem CID	18462 131278 (1R) 218580 (1S) 43833349 (4R) 3057042 (4S)
UNII	D8D049375Q Y Y6075I4FXE (1R) Y 9TLZ01S15L (1S) Y
UN number	1759
CompTox Dashboard (EPA)	DTXSID60863113
InChI InChI=1S/C10H16O4S/c1-9(2)7-3-4-10(9,8(11)5-7)6-15(12,13)14/h7H,3-6H2,1-2H3,(H,12,13,14) Y Key: MIOPJNTWMNEORI-UHFFFAOYSA-N Y
SMILES CC1(C2CCC1(C(=O)C2)CS(=O)(=O)O)C O=S(=O)(O)CC12C(=O)CC(CC1)C2(C)C
Properties
Chemical formula	C10H16O4S
Molar mass	232.29 g·mol−1
Melting point	195 °C (decomposes)
Acidity (pKa)	1.2
Hazards
Safety data sheet (SDS)	External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 Â°C [77 Â°F], 100 kPa). N verify (what is YN ?) Infobox references

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This compound is commercially available. It can be prepared by sulfonation of camphor with sulfuric acid and acetic anhydride:^[1]

Although this reaction appears to be a sulfonation of an unactivated methyl group, the actual mechanism is believed to involve a retro-semipinacol rearrangement, deprotonation next to the tertiary carbocation to form an alkene, sulfonation of the alkene intermediate, and finally, semipinacol rearrangement to re-establish the ketone function.^[2]

In organic synthesis, CSA and its derivatives can be used as resolving agents for chiral amines and other cations.^[3][4] The synthesis of osanetant was an example of this. 3-bromocamphor-8-sulfonic acid was used in the synthesis of enantiopure devazepide.^[5]

Camphorsulfonic acid is also being used for the synthesis of quinolines.^[6] Camphorsulfonic acid is used in some pharmaceutical formulations, where is it referred to as camsilate or camsylate, including trimetaphan camsilate and lanabecestat camsylate. Some studies (c.f. Lednicer) support that D-CSA was used for the resolution of Chloramphenicol.