Novel Synthesis of Alkenes via Triethylborane-Induced Free-Radical Reactions of Alkyl Iodides and <i>β</i>-Nitrostyrenes
作者:Ju-Tsung Liu、Yeong-Jiunn Jang、Yuh-Kuo Shih、Shin-Ru Hu、Cheng-Ming Chu、Ching-Fa Yao
DOI:10.1021/jo010213m
日期:2001.9.1
iodides 6 and 8 or tertiary alkyl iodides 9, 11, and 13, in the presence of 2 and air as radical initiator. The generation of the only product (E)-alkenes can be explained by the generation of the benzylic radical A and/or B as the intermediate only and the mechanism is similar to Scheme 1. Both (E)- and (Z)-16a-c are generated when (E)- and (Z)-15a-c are used to react with adamantyl radical under similar
(E)-β-硝基苯乙烯1和三乙基硼烷2或三环己基硼烷4在室温下在空气中存在氧气作为自由基引发剂的条件下的反应产生高产率的反式烯烃(E)-3或(E)- 5,当1与由仲烷基碘化物6和8或叔烷基碘化物9制备的不同基团反应时,也可以制备中等至高产率的不同的(E)-烯烃(E)-5、7、10、12和14。参照图11和13,在2和空气的存在下作为自由基引发剂。唯一产物(E)-烯烃的产生可以通过仅作为中间体的苄基基团A和/或B的产生来解释,其机理与方案1相似。(E)-和(Z)-16a当(E)-和(Z)-15a-c与金刚烷基在相似条件下反应时,生成-c。当使用(E)-或(Z)-15d与金刚烷基自由基反应时,仅观察到(Z)-16d。(E)-和/或(Z)-烯烃的生成可以通过A和/或B自由旋转以生成A'和/或B'来解释,反之亦然,并且该机理被认为是通过NO 2 /烷基取代的自由基反应,如方案2所示。