Iron-catalyzed carbometalation of propargylic and homopropargylic alcohols
Iron-catalyzed carbometalation of propargylic and homopropargylic alcohols
复制标题
DOI：
10.1021/ja0647708
复制
发表时间：
2006-11-29
影响因子：
15
通讯作者：
Ready, Joseph M.
中科院分区：
文献类型：
--
作者：
Zhang, Donghui;Ready, Joseph M.
炔的亲核加成反应是合成烯烃的一种有吸引力的方法。这一策略的障碍包括对许多有机金属试剂的炔的低反应性和与控制加成的区域选择性相关的困难。在这里，我们表明，Fe（III）盐是有效的预催化剂的炔的碳化。伯和仲炔丙醇和高炔丙醇与烷基和芳基格氏试剂反应以提供Z-烯丙基和-高烯丙基醇作为单一立体异构体和区域异构体。烷基化和芳基化发生在醇的远端。常见的氧保护基和叔氮是容许的。中间体乙烯基镁或铁物种可以被各种亲电试剂捕获，包括醛，烯丙基溴和N-溴代琥珀酰亚胺。二炔底物经历不寻常的加成/环化反应以生成环状二烯。简要讨论了机制。
Nucleophilic addition to alkynes represents an attractive approach to the synthesis of olefins. Obstacles to this strategy include the low reactivity of alkynes toward many organometallic reagents and difficulties associated with controlling the regioselectivity of addition. Here we demonstrate that Fe(III) salts are effective precatalysts for the carbometalation of alkynes. Primary and secondary propargylic and homopropargylic alcohols react with alkyl and aryl Grignard reagents to provideZ-allylic and -homoallylic alcohols as single stereo and regioisomers. Alkylation and arylation occur distal to the alcohol. Common oxygen protecting groups and tertiary nitrogens are tolerated. The intermediate vinyl magnesium or iron species can be trapped with a variety of electrophiles including aldehydes, allyl bromide, andN-bromosuccinimide. Diyne substrates undergo an unusual addition/cyclization reaction to generate cyclic dienes. A brief discussion of mechanism is included.