作者:Irene Walz、Andreas Bertogg、Antonio Togni
DOI:10.1002/ejoc.200700156
日期:2007.6
Vanadium(IV) species generated in situ from V(salen)Cl2 complexes (1) by reaction with 2 equiv. of AgSbF6 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
V(salen)Cl2 络合物 (1) 通过与 2 当量反应原位生成的钒 (IV) 物质。AgSbF6 是 Nazarov 环化的有效催化剂。因此,在室温下,在 2 mol% 催化剂的存在下,带有 α-酯基团的二烯基酮以良好的产率有效地转化为相应的环戊烯酮。在这种条件下,在 1,4-dien-3-one 系统的位置 1 处带有给电子基团的底物在几分钟内发生完全转化。 (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)