Copper mediated defluorinative allylic alkylation of difluorohomoallyl alcohol derivatives directed to an efficient synthetic method for (Z)-fluoroalkene dipeptide isosteres
作者:Daisuke Watanabe、Minoru Koura、Akio Saito、Hikaru Yanai、Yuko Nakamura、Midori Okada、Azusa Sato、Takeo Taguchi
DOI:10.1016/j.jfluchem.2011.03.007
日期:2011.5
fluorine-substituted allylic alcohol 12 in an high yield and in an excellent Z selective manner. Subsequent imidate Claisen rearrangement of the allylic alcohol 12 proceeded with a complete 1,3-chirality transfer to give the fluoroalkene dipeptide isostere structure 14 after the final conversion of the primary alcohol 20 into the carboxylic acid form.
光学纯的O-甲硅烷基化的(S)-2-甲基-3-羟基丙醛10a与铟介导的溴二氟丙烯的二氟烯丙基化反应提供了具有低非对映选择性的相应二氟均烯丙基醇11a,但光学纯度没有降低。通过与三烷基铝和Cu(I)体系或Grignard试剂以及催化量的CuI体系在THF中反应,二氟高烯丙基醇的每个非对映异构体的脱氟烯丙基烷基化反应有效地进行,从而以高收率和高产率获得了氟取代的烯丙基醇12极好的Z选择性方式。随后的亚胺酸酯克莱森重排烯丙醇12在伯醇20最终转化为羧酸形式后,进行完全的1,3-手性转移,得到氟代烯烃二肽等排结构14。