Preparation of two trifluoromethyl analogs of JH-III, methyl 10,11-epoxy-7,11-dimethyl-3-trifluoromethyldodeca-2, 6-dienoate (1a) and methyl 10,11-epoxy-3,11-dimethyl-7-trifluoromethyldodeca-2,6-dienoate (1b) is described. The stereochemistry of trisubstituted double bonds, bearing one trifluoromethyl substituent, could be assigned easily by 19F NMR spectroscopy. Some peculiarities of the Wittig reactions
制备JH-III的两个三氟甲基类似物,即10,11-环氧-7,11-甲基-3-甲基三氟甲基dodeca-2,6-二烯酸酯(1a)和10,11-环氧-3,11-二甲基-7甲基描述了-三氟甲基十二烷基-2,6-二烯酸酯(1b)。带有一个三氟甲基取代基的三取代双键的立体化学可通过19 F NMR光谱轻松确定。指出了三氟甲基酮的Wittig反应的一些特征。
Synthesis of β-CF3 ketones from trifluoromethylated allylic alcohols by ruthenium catalyzed isomerization
This work describes the optimization process for the synthesis of β-trifluoromethylated ketonesfrom trifluoromethylated allylicalcohols. This transformation proceeds through a ruthenium catalyzed isomerization under mild conditions with high atom economy. The effect of the CF3 group was analyzed and it provides fundamental insights into the isomerization reaction.
Synthesis of Fluorine Analogs of Vitamin E. III. Synthesis of 2-(4,8-Dimethyl-12-(trifluoromethyl)tridecyl)-2,5,7,8-tetramethyl-6-chromanol and 2-(4,12-Dimethyl-8-(trifluoromethyl)tridecyl)-2,5,7,8-tetramethyl-6-chromanol.
2-[4, 8-Dimethyl-12-(trifluoromethyl)tridecyl]-2, 5, 7, 8-tetramethyl-6-chromanol and 2-[4, 12-dimethyl-8-(trifluoromethyl)tridecyl]-2, 5, 7, 8-tetramethyl-6-chromanol, were synthesized by means of the Wittig reaction using the phosphonium salt of 2-(3-chloropropyl)-2, 5, 7, 8-tetramethyl-6-chromanol.
As part of a search for biologically active analogues of vitamin E, fluorine derivatives of tocotrienol and related compounds were synthesized by the ring-closure of trifluoroprenols with trimethylhydroquinone. For this purpose, the trifluoroprenols were synthesized by the Wittitg-Horner reaction of trifluoroacetone or its prenyl homologues with triethylphosphonoacetate followed by reduction of the trifluoromethylated acrylic ester derivatives. Although 4, 4, 4-trifluoroprenol itself did not react with the hydroquinone, 7, 7, 7-trifluorodiprenol and higher prenols gave 6-chromanols with a trifluofomethylated side-chan.
Synthesis of fluorine analogues of vitamin E. II. Synthesis of 2-(3-chloropropyl)-2,5,7,8-tetramethyl-6-chromanol and its application for stereocontrolled Wittig reaction with trifluoromethyl ketones.
As the extension of our research to find a biologically active analogue of vitamin E, a more convenient method for the synthesis of fluorine derivatives of 6-chromanol than our previous method was developed. Thus, 2-(3-chloropropyl)-2, 5, 7, 8-tetramethyl-6-chromanol (3) was synthesized by the reaction of 6-chloro-3-methyl-2-hexen-1-ol (2) and trimethylhydroquinone, and the phosphonium ylides (5 and 6) derived from 3 were condensed with trifluoromethylated ketones to give 2-(trifluoroprenyl)-6-chromanol compounds (1a, 1b and 1c) by means of the Wittig reaction as modified by Schlosser. By the use of this revised procedure, the total yields of the chromanols were much improved. Further, the modified Wittig reaction showed higher stereoselectivity than the previous syntheses of these compounds. The double bonds of the side-chain of the products were reduced to give fluorine derivatives of tocopherol analogues. Compound 3 was found to be a useful intermediate for the facile synthesis of vitamin E derivatives.
作为我们寻找维生素 E 生物活性类似物研究的延伸,开发了一种比我们之前的方法更方便的 6-苯并二氢吡喃醇氟衍生物的合成方法。因此,通过6-氯-3-甲基-2-己烯-1-醇(2)的反应合成2-(3-氯丙基)-2,5,7,8-四甲基-6-苯并二氢吡喃醇(3)和三甲基氢醌,以及由3衍生的鏻叶立德(5和6)与三氟甲基化酮缩合,通过Schlosser改进的Wittig反应得到2-(三氟异戊二烯基)-6-苯并二氢吡喃醇化合物(1a、1b和1c)。通过使用这一修改后的程序,苯并二氢吡喃醇的总产率得到了很大提高。此外,改进的维蒂希反应比以前合成的这些化合物显示出更高的立体选择性。产物侧链双键被还原,得到生育酚类似物的氟衍生物。化合物 3 被发现是一种有用的中间体,可用于轻松合成维生素 E 衍生物。