AuBr<sub>3</sub>- and Cu(OTf)<sub>2</sub>-Catalyzed Intramolecular [4 + 2] Cycloaddition of Tethered Alkynyl and Alkenyl Enynones and Enynals: A New Synthetic Method for Functionalized Polycyclic Hydrocarbons
作者:Naoki Asao、Kenichiro Sato、Menggenbateer、Yoshinori Yamamoto
DOI:10.1021/jo0500434
日期:2005.4.1
Cu(OTf)2 catalyst, the corresponding dihydronaphthyl ketone products 13 and 15 were obtained in high yields, respectively. The present formal [4 + 2] intramolecular cycloaddition proceeds most probably through the coordination of the triple bond at the ortho position of substrates to Lewis acids, the formation of benzopyrylium ate complex 16 via the nucleophilic addition of the carbonyl oxygen atom, the
用催化量的(ClCH 2)2中的AuBr 3处理其中碳链连接在羰基上的链状炔基烯酮8,萘甲酮9的产率高至高(自上而下的方法)。类似地,AuBr 3的催化的benzannulations 10,在该系绳从炔末端延长,也顺利进行中的碳,和环化萘基酮11以高收率(自下而上的方法)获得。类似地,当用Cu(OTf)2处理两种束缚的烯基烯酮12和14时催化剂,分别以高收率得到相应的二氢萘基酮产物13和15。当前的形式上的[4 + 2]分子内环加成反应最可能是通过底物与路易斯酸邻位的三键配位,通过羰基氧原子的亲核加成形成苯并吡啶鎓盐配合物16,反向电子而进行的。需求类型Diels-将被束缚的炔烃或烯烃加成到酯配合物中,以及随后的键重排。