Cationic vanadium (IV) complexes as efficient catalysts for Nazarov cyclizations

I Walz, A Bertogg, A Togni

Index: Walz, Irene; Bertogg, Andreas; Togni, Antonio European Journal of Organic Chemistry, 2007 , # 16 p. 2650 - 2658

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Citation Number: 13

Abstract

Abstract Vanadium (IV) species generated in situ from V (salen) Cl 2 complexes (1) by reaction with 2 equiv. of AgSbF 6 are effective catalysts for Nazarov cyclizations. Thus, dialkenyl ketones bearing α-ester groups are efficiently converted to corresponding cyclopentenones in good yields at room temperature, in the presence of 2 mol-% catalyst. Under such conditions full conversion takes place within minutes for substrates bearing an ...