C−C-Bond Formation by the Palladium-Catalyzed Cycloisomerization/Dimerization of Terminal Allenyl Ketones: Selectivity and Mechanistic Aspects
作者:A. Stephen K. Hashmi、Thorsten L. Ruppert、Thomas Knöfel、Jan W. Bats
DOI:10.1021/jo970837l
日期:1997.10.1
conditions, besides the normal functional group tolerance known for palladium-catalyzed reactions, an interesting selectivity was observed with functional groups that are known to react either in palladium-catalyzed reactions or reactions catalyzed by other transition-metals. Thus aryl halides, terminal alkynes, 1,6-enynes, and alpha-allenic alcohols were tolerated. In the latter example the selective reaction
研究了末端烯基酮1到2,4-二取代的呋喃3的钯催化的环化/二聚化的范围。简化和改善的条件几乎只提供了二聚体3,仅伴有痕量的易于分离的单体2。完全抑制了3的异构体,即未共轭的酮4的形成。在这些温和的条件下,除了钯催化的反应对正常官能团的耐受性外,还发现了与已知在钯催化的反应或由其他过渡金属催化的反应中反应的官能团的有趣选择性。因此,可以耐受芳基卤化物,末端炔烃,1,6-烯炔和α-烯丙醇。在后一实例中,实现了两种不同的烯丙基中仅一种的选择性反应。