Selective Synthesis of Allylated Oxime Ethers and Nitrones Based on Palladium-Catalyzed Allylic Substitution of Oximes
作者:Hideto Miyabe、Kazumasa Yoshida、Valluru Krishna Reddy、Akira Matsumura、Yoshiji Takemoto
DOI:10.1021/jo050632+
日期:2005.7.1
transition-metal-catalyzed allylic substitution was examined. The oxygen atom of oxime acted as a reactive nucleophile in the reaction of a π-allyl palladium complex. In the presence of Pd(PPh3)4, the allylic substitution of oximes with allylic carbonate afforded the linear O-allylated oxime ethers selectively without a base. In contrast, the palladium-catalyzed reaction with allylic acetate proceeded smoothly
考察了肟作为亲核试剂在过渡金属催化的烯丙基取代中的活力。肟的氧原子在π-烯丙基钯配合物的反应中充当反应性亲核试剂。在Pd(PPh 3)4存在下,用碳酸烯丙酯进行肟的烯丙基取代,可选择性地得到线性的O-烯丙基化肟醚,而无需碱。相反,在存在K 2 CO 3或Et 2 Zn作为碱的情况下,钯与乙酸烯丙酯的反应顺利进行。通过使用钯(II)催化剂选择性地形成硝酮。在Pd(cod)Cl 2存在下通过与肟的氮原子反应,在无溶剂条件下,用乙酸烯丙酯将肟的烯丙基取代提供了N-烯丙基化的硝酮。