Posteado por: irisbelguzman23 | Febrero 27, 2009

Abtract: Enantioselective Reduction of Prochiral β-Halogenated Aryl Ketones for Organic Synthesis of Chiral Oxetanes

Enantio-pure oxetanes are important as start materials for a large variety of applications in organic synthesis. These oxetanes are mainly use in the synthesis of chiral β-amino alcohols of pharmaceutical importance for the treatment of anxiety and depression. A new synthetic method for the formation of enantio-pure oxetanes using our catalyst complex (EG-DPP), derived from ethylene glycol and diphenyl prolinol, and borane, was investigated. Presently, we are studying the enantioselective reductions of prochiral β-halogenated aryl ketones to their corresponding β-halogenated alcohol. We have performed the asymmetric reduction of the 3-chloropropiophenone using 1 mol % to 10 mol % of our complex catalyst EG-DPP, affording the pure product after recrystallization in hexane in 99% ee with 5 mol % of catalyst. To establish the cyclization reaction, the 1-phenyl oxetane was obtained by the reduction of racemic 3-chloropropiophenone and treatment of the 3-chloro phenyl propanol with potassium tert-butoxide. Future organic synthesis of oxetanes with chiral 3-chloropropiophenone and other β-halogenated aryl ketones are under investigation.


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