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Synlett 2009(4): 683-684  
DOI: 10.1055/s-0028-1087717
SPOTLIGHT
© Georg Thieme Verlag Stuttgart ˙ New York

Camphorsulfonic Acid: A Versatile and Useful Reagent in Organic Synthesis

Mónica S. Estevão*
REQUIMTE, Departamento de ­Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
e-Mail: monica.estevao@gmail.com;
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Publication History

Publication Date:
16 February 2009 (online)

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Introduction

Camphorsulfonic acid (CSA) (or Reychler’s acid) 1, is a white crystalline powder, hygroscopic, very soluble in ethanol and melts at 198 ˚C.

It is commercially available but it can be easily prepared from camphor by treatment whit sulfuric acid and acetic anhydride (Figure  [¹] ). [¹]

CSA is the first C10-substituted camphor derivative obtained, [¹] it is frequently used not only in asymmetric synthesis as chiral starting material [²] (such as its derivative 10-camphorsulfonyl chloride) but also as a useful catalyst in natural product synthesis. [³]

Moreover, CSA is widely used for the diasteriomeric salt resolution. [4] [5]

Scheme 1 Preparation of camphorsulfonic acid