Copper mediated defluorinative allylic alkylation of difluorohomoallyl alcohol derivatives directed to an efficient synthetic method for (Z)-fluoroalkene dipeptide isosteres
Copper mediated defluorinative allylic alkylation of difluorohomoallyl alcohol derivatives directed to an efficient synthetic method for (Z)-fluoroalkene dipeptide isosteres
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DOI：
10.1016/j.jfluchem.2011.03.007
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发表时间：
2011-05
影响因子：
1.9
通讯作者：
D. Watanabe;Minoru Koura;A. Saito;H. Yanai;Yuko Nakamura;Midori Okada;Azusa Sato;T. Taguchi
中科院分区：
文献类型：
--
作者：
D. Watanabe;Minoru Koura;A. Saito;H. Yanai;Yuko Nakamura;Midori Okada;Azusa Sato;T. Taguchi
光学纯的O-甲硅烷基化的（S）-2-甲基-3-羟基丙醛10a与溴二氟丙烯在铟的介导下发生二氟烯丙基化反应，得到了相应的二氟高烯丙醇11 a，其非对映选择性较低，但光学纯度没有降低。二氟高烯丙醇的各非对映异构体在THF中与三烷基铝和Cu（I）体系或格氏试剂和催化量的CuI体系反应，有效地进行了脱氟烯丙基烷基化，以高产率和优异的Z选择性方式得到氟取代烯丙醇12。随后烯丙醇的亚氨酸Claisen重排12进行完全的1，3-手性转移，在伯醇20最终转化为羧酸形式后，得到氟烯烃二肽等排体结构14。
Difluoroallylation of optically pureO-silylated (S)-2-methyl-3-hydroxypropanal10awith bromodifluoropropene mediated by indium provided the corresponding difluorohomoallyl alcohol11awith low diastereoselectivity, but without a decrease in optical purity. Defluorinative allylic alkylation of each diastereomer of the difluorohomoallyl alcohol efficiently proceeded by the reaction with trialkylaluminium and Cu(I) system or Grignard reagent and a catalytic amount of CuI system in THF to give the fluorine-substituted allylic alcohol12in an high yield and in an excellentZselective manner. Subsequent imidate Claisen rearrangement of the allylic alcohol12proceeded with a complete 1,3-chirality transfer to give the fluoroalkene dipeptide isostere structure14after the final conversion of the primary alcohol20into the carboxylic acid form.