An expedient synthesis of α,α-difluoro-β-hydroxy ketones via decarboxylative aldol reaction of α,α-difluoro-β-keto acids with aldehydes
作者:Da-Kang Huang、Zhong-Liang Lei、Yu-Jun Zhu、Zhen-Jiang Liu、Xiao-Jun Hu、Hai-Fang Mao
DOI:10.1016/j.tetlet.2017.07.060
日期:2017.8
A novel decarboxylative aldol reaction of α,α-difluoro-β-keto acids with aldehydes in the absence of any base and metal catalysts has been developed. This reaction provides a highly convenient and efficient method for the synthesis of structurally diverse α,α-difluoro-β-hydroxy ketones in good to excellent yields.
present an efficient method for the construction of α,α-difluoro-β-hydroxy ketones. The La(OTf)3-catalyzed aldol reaction between difluoroenol O-Boc (Boc = tert-butyloxycarbonyl) esters and carbonyl compounds affords α,α-difluoro-β-hydroxy ketones in good yield. The key reagents of this reaction are the difluoroenol O-Boc esters, which are easily synthesized from trifluoromethyl alcohols in two steps
α-fluorinated ketones with m-chloroperbenzoic acid (m-CPBA) under mild conditions. The yield of the esters was influenced by the choice of solvent, base, and substituent on the aryl group of the ketones. 4-Methoxyphenyl substituted fluoroketones were oxidized almost quantitatively with m-CPBA within 10 min to 12 h at room temperature using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a cosolvent with CH2Cl2
被有效地用α-氟化酮的拜尔-维利格氧化制备α-氟化酯米氯过苯甲酸(米温和条件下-CPBA)。酯的产率受酮的芳基上的溶剂,碱和取代基的选择影响。在室温下,使用1,1,1,3,3,3-六氟-2-丙醇(HFIP)与CH 2 Cl作为助溶剂,在10分钟至12小时内,用m -CPBA几乎定量地氧化了4-甲氧基苯基取代的氟代酮。2(1:1,v / v)和水性缓冲液(KH 2 PO 4-NaOH,pH 7.6)作为添加剂。α-氟代酮的氧化反应速率高于相应的非氟代酮的氧化反应速率。氟甲基芳基酮的α位上的氟原子增强了BAeyer-Villiger氧化反应的活性。
Decarboxylative aldol reaction of α,α-difluoro-β-ketocarboxylate salt: a facile method for generation of difluoroenolate
We developed a decarboxylativealdolreaction using α,α-difluoro-β-ketocarboxylate salt, carbonyl compounds, and ZnCl2/N,N,N′,N′-tetramethylethylenediamine. The generation of difluoroenolate proceeded smoothly under mild heating to provide α,α-difluoro-β-hydroxy ketones in good to excellent yield (up to 99%). The α,α-difluoro-β-ketocarboxylate salt was bench stable and easy to handle under air, which
我们使用 α,α-二氟-β-酮羧酸盐、羰基化合物和 ZnCl 2 / N , N , N ', N '-四甲基乙二胺开发了脱羧醛醇反应。二氟烯醇化物的生成在温和加热下顺利进行,以良好至优异的产率(高达 99%)提供 α,α-二氟-β-羟基酮。α,α-二氟-β-酮基羧酸盐具有台架稳定性,在空气中易于操作,实现了一种方便、环保的二氟亚甲基化合物合成方法。