Synthesis and characterization of β-haloalkenyl-λ3-bromanes:: Stereoselective Markovnikov addition of difluoro(aryl)-λ3-bromane to terminal acetylenes
Synthesis and characterization of β-haloalkenyl-λ3-bromanes:: Stereoselective Markovnikov addition of difluoro(aryl)-λ3-bromane to terminal acetylenes
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DOI：
10.1021/ja051690f
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发表时间：
2005-08-03
影响因子：
15
通讯作者：
Frohn, HJ
中科院分区：
文献类型：
--
作者：
Ochiai, M;Nishi, Y;Frohn, HJ
本文首次报道了高价β-卤代烯基-λ3-溴基的合成、分离和表征。在BF3-i-Pr2O的活化下暴露末端炔，导致三键以Markovnikov方式发生氟-λ -溴化，立体选择性地产率高的(E)-β-氟烯基-λ -溴化。根据取代基的不同，5-氯-1-戊烷会发生多米诺λ3-溴化-氯移-氟化或λ3-溴化-氯移-烷基移-氟化反应，并以高收率立体选择性地提供(E)-β-氯烯基-λ3-溴化。β-氯烯基-λ3-溴在分子中含有F、Cl、Br三种卤素原子。
Reported here for the first time are the synthesis, isolation, and characterization of hypervalent β-haloalkenyl-λ3-bromanes. Exposure of terminal alkynes top-trifluoromethylphenyl(difluoro)-λ3-bromane activated by BF3-i-Pr2O resulted in fluoro-λ3-bromanation of the triple bonds in a Markovnikov fashion, yielding (E)-β-fluoroalkenyl-λ3-bromanes stereoselectively in good yields. 5-Chloro-1-pentynes undergo domino λ3-bromanation−chlorine shift−fluorination or λ3-bromanation−chlorine shift−alkyl shift−fluorination reaction, depending on the substituents and afford (E)-β-chloroalkenyl-λ3-bromanes stereoselectively in high yields. The β-chloroalkenyl-λ3-bromanes contain three kinds of halogen atoms, F, Cl, and Br, in the molecule.