A microbially-based approach for the synthesis of chiral secondary alcohols bearing the difluoromethyl or chlorodifluoromethyl group
摘要:
A synthetic approach to both enantiomers of the secondary alcohols [Ph(CH2)n CH(OH)CXF2 (n = 0-2) C6H13(CH2)n CH(OH)CFX2 (n = 0 or 2) and CXF2CH(OH)CH2CO2Et [X = H or Cl], involving the stereoselective hydrolysis of ester derivatives, is described. The absolute configurations of these difluoromethylated or chlorodifluoromethylated molecules were determined.
An Efficient and General Method for the Reformatsky-Type Reaction of Chlorodifluoromethyl Ketones with Carbonyl Compounds Giving α,α-Difluoro-β-hydroxy Ketones
作者:Manabu Kuroboshi、Takashi Ishihara
DOI:10.1246/bcsj.63.428
日期:1990.2
Specific activation of zinc metal with the metal salt is essential to achieve high efficiency of the reaction, depending upon the structures of the chlorodifluoromethyl ketones and the carbonyl compounds employed. In-situ formed intermediates in these reactions were successfully detected by 19F NMR spectroscopy, which suggests that their structure is not an α-metallo ketone but an oxygen-metallated
氯二氟甲基酮 CF2ClCOR,其中 R 是烷基、芳基和 1-炔基,在酸洗锌粉和氯化铜 (I) 或银存在下,与多种醛或酮发生 Reformatsky 型羟醛反应醋酸盐得到相应的 α,α-二氟-β-羟基酮,收率很好。根据氯二氟甲基酮和所用羰基化合物的结构,用金属盐对锌金属进行特定活化对于实现反应的高效率是必不可少的。这些反应中原位形成的中间体通过 19F NMR 光谱成功检测到,这表明它们的结构不是 α-金属酮,而是具有锌 (II) 金属作为抗衡阳离子的氧金属化物质。
A convenient preparative method for α-trifluoromethyl amines
α-Trifluoromethyl amines (IV) were prepared in three steps: preparation of α-trifluoromethyl ketones (I), their conversion tobenzyloximes (II), and reduction of the oximes (II) with lithium aluminium hydride and sodium methoxide. For example, α-trifluoromethyltridecylamine was obtained from the reduction of trifluoromethyl dodecyl ketone benzyl oxime.
A convenient synthesis of 2,2-difluoro enol silyl ethers from chlorodifluoromethyl ketones
作者:Masayuki Yamana、Takashi Ishihara、Teiichi Ando
DOI:10.1016/s0040-4039(00)81449-5
日期:——
Various chlorodifluoromethyl ketones can be converted to the corresponding 2,2-difluoro enol silylethers in good yields, by the action of zinc dust and chlorotrimethylsilane in dry acetonitrile at 60°C.
Study on the effect of diand trifluoromethyl groups on the baeyer-villiger reaction
作者:Tomoya Kitazume、Junichi Kataoka
DOI:10.1016/s0022-1139(96)03500-2
日期:1996.10
Case studies of the Baeyer-Villiger reaction applied to di- and trifluoromethylketone derivatives and the effect of the fluoromethyl groups on the Baeyer-Villiger reaction, are described.
Brigaud Thierry, Doussot Pascale, Portella Charles, J. Chem. Soc. Chem. Commun, (1994) N 18, S 2117-2118
作者:Brigaud Thierry, Doussot Pascale, Portella Charles