Chiral symmetry breaking: Experimental results and computer analysis of a liquid-phase autoxidation

✍ Scribed by Thomas Buhse; Dominique Lavabre; Jean-Claude Micheau; Prof. Dr. Wolfram Thiemann

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 445 KB
• Volume: 5
• Category: Article
• ISSN: 0899-0042
• DOI: 10.1002/chir.530050512

✦ Synopsis

The autoxidation of tetralin is treated as a model reaction system to define the applicability of stereospecific autocatalysis. This concept, predicting a spontaneous amplification of enantiomeric excess generated by an autocatalytic chemical reaction, is used in several theoretical models as an explanation for the origin of natural optical activity. The reaction system investigated obeys the basic criteria of these models: a chiral intermediate (tetralin hydroperoxide) is produced from an achiral substrate (tetralin) via an autocatalytic pathway where the feedback mechanism is expected to generate a state of broken chiral symmetry. In order to test the amplification capacity of this reaction a computer analysis of the kinetic scheme is performed. This simulation is derived from the known kinetic scheme of autoxidation and is validated by fitting the experimentally observed data of hydroperoxide evolution. Calculations show that this model allows powerful amplification of enantiomeric excess and a transient amplication of the optical rotation. It is also demonstrated that the model system exhibits pronounced sensitivity toward any loss of absolute configuration of the involved chiral species. Since an amplification effect results exclusively at a high degree of stereoselectivity, it is conciuded that stereospecific autocatalysis is possible in systems which show template reactions, crystallization, or colloidal effects.