化学学报 ›› 2013, Vol. 71 ›› Issue (09): 1243-1247.DOI: 10.6023/A13050543 上一篇    下一篇

研究通讯

钯催化芳基乙炔对氧/氮杂苯并降冰片烯开环反应研究

陈花磊, 李嗣锋, 徐建斌, 杨清镜, 刘珊珊, 周永云, 黄超, 樊保敏   

  1. 云南民族大学 民族药资源化学国家民委-教育部重点实验室 昆明 650500
  • 收稿日期:2013-05-20 出版日期:2013-09-14 发布日期:2013-06-27
  • 通讯作者: 樊保敏,E-mail:adams.bmf@hotmail.com;Fax:0086-0871-65913103 E-mail:adams.bmf@hotmail.com
  • 基金资助:

    项目受国家自然科学基金(No. 21162040, 20902080, 21362043)和云南省应用基础研究计划项目(No. 2012FB170)资助

Palladium-Catalyzed Ring-Opening Reaction of Oxa/Azabenzonorbornadienes with Aryl Acetylenes

Chen Hualei, Li Sifeng, Xu Jianbin, Yang Qingjing, Liu Shanshan, Zhou Yongyun, Huang Chao, Fan Baomin   

  1. Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan University of Nationalities, Kunming 650500, China
  • Received:2013-05-20 Online:2013-09-14 Published:2013-06-27
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21162040, 20902080, 21362043) and the Applied Basic Research Program of Yunnan Province (No. 2012FB170).

过渡金属催化的碳亲核试剂对氧/氮杂苯并降冰片烯的开环反应是合成氢化萘衍生物的有效方法之一. 在该类反应中, 采用末端炔烃作为碳亲核试剂在反应操作、底物适用范围等多个方面都具有已报道的各种有机金属亲核试剂所不具备的优势. 目前, 对末端炔烃与氧/氮杂苯并降冰片烯的开环反应的研究进展有限, 只有Ni(dppe)Cl2/ZnCl2/Zn和手性的Rh两种催化体系被应用到该类反应当中, 但都面临一些不足. 为该类反应开发简单有效的新型催化体系仍然具有重要的意义和价值. 我们通过研究发现: PdCl2与Xantphos的配合物是芳基乙炔对氧/氮杂苯并降冰片烯亲核开环反应的有效催化剂. 在优化后的反应条件下, 该Pd催化剂具有良好的催化活性和底物适应能力, 能够实现各种取代的芳基乙炔对氧/氮杂苯并降冰片烯的亲核加成, 并以较好的收率生成目标开环产物.

关键词: 钯, 芳基乙炔, 氧杂苯并降冰片烯, 氮杂苯并降冰片烯, 开环反应

The transition-metal catalyzed ring opening reaction of oxa/azabenzonorbornadienes with carbo-nucleophiles has played an important role in the synthesis of tetrahydronaphthalene structures, which widely exist in natural products and bioactive molecules. Caused by the easy manipulation of reaction procedures and the less limits of suitable substrates, the ring opening reaction of oxa/azabenzonorbornadienes with terminal alkynes as nucleophiles has more potential in organic synthesis than with the organometal nucleophiles, such as zinc reagents, lithium reagents, Grignard reagents, aluminium reagents, organoboronic acids and zirconium reagents. However, only limited progress had been achieved for the ring opening reaction of oxa/azabenzonorbornadienes with terminal alkynes. Up to now, only a Ni(dppe)Cl2/ZnCl2/Zn catalytic system and a chiral rhodium catalyst had been developed for this reaction. Unfortunately, the former formed a relatively complicated reaction system, and suffered from the absence of chiral control ability. The latter was generated by composing of[Rh(OAc)(C2H4)2]2 with (R)-DTBM-segphos and could result in high enantioselectivity. But the scope of suitable substrates for it was too limited, and only sterically bulky acetylenes were found useful. Developing new and efficient catalysts for this reaction is still interesting and desirable. As the continuation of our study on transition-metal catalyzed reactions between norbornadienes and terminal alkynes, we surprisingly found that the complex of PdCl2 and Xantphos could catalyze the ring opening reaction of oxabenzonorbornadiene 1a with p-methoxyphenylacetylene 2a smoothly. The optimization of reaction conditions showed that 1,2-dichloroethane was the only effective solvent and 70 ℃ was the proper reaction temperature. The investigation on the scope of suitable substrates showed that this new developed PdCl2/Xantphos catalyst had good tolerance for various functional groups. Under the promotion of this Pd catalyst, a series of oxa/azabenzonorbornadienes could react with various aryl acetylenes, having different substituents on the phenyl rings, smoothly to generate the ring opening products in good yields. Further efforts to design and synthesize new Pd catalysts to realize the asymmetric version of the ring opening reaction of oxa/azabenzonorbornadienes with terminal alkynes are still in progress.

Key words: palladium, aryl acetylene, oxabenzonorbornadiene, azabenzonorbornadiene, ring-opening reaction