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Synlett 2009(1): 155-156  
DOI: 10.1055/s-0028-1083138
SPOTLIGHT
© Georg Thieme Verlag Stuttgart ˙ New York

Ozone: A Versatile Oxidizing Agent in Academic Syntheses and Industrial Processes

Giovanni Wilson Amarante*
Instituto de Química, Universidade Estadual de Campinas, UNICAMP, C.P. 6154, CEP 13083-970, Campinas, São Paulo, Brasil.
e-Mail: amarante@iqm.unicamp.br;
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Publication History

Publication Date:
12 December 2008 (online)

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Introduction

Due to its simple preparation (O3 from O2) and efficiency, ozone has attracted the attention of academic and industrial sectors as an oxidizing agent, mainly for the clean and efficient oxidative cleavage of double bonds (ozono­lysis). [¹]

Ozone was discovered in 1847 by Schönbein who observed that ozone did not convert organic compounds to the highest oxidation level (CO2, H2O), but led them to intermediate oxidative levels such as carboxylic acids. Some years later, Harries demonstrated the high applicability of ozone in organic reactions, especially with double bond oxidations. [²]

Based on his own results and data available in the literature, Criegee has proposed a mechanism to explain oxidative cleavage during ozonolysis. According to Criegee, a molozonide and 1,2,4-trioxolane (ozonide) are the intermediates of this reaction. Experimental evidence confirmed this proposition and this mechanism is currently accepted (Scheme  [¹] ). [³]

Scheme 1 Mechanistic proposal for ozonolysis

The ozonide intermediate can afford ketones, aldehydes and alcohols after reductive workups, while oxidative conditions can furnish ketones or carboxylic acids.

Ozone has been applied to the development of new synthetic methodologies, [4] key intermediates in the total synthesis of natural and bioactive compounds [5] and new protocols in the pharmaceutical industries. [6]