Pd-catalysed procedures for the direct Heck arylation of diethyl vinylphosphonate with various aryl or heteroaryl halides toward the synthesis of diethyl2-(aryl)vinylphosphonates are reported. Several homogeneous catalytic systems (i.e. Herrmann palladacycle, Nolan (NHC)-palladium catalyst, Pd(OAc)2/PPh3) were used and compared within the study. High conversions and selectivities were achieved under
报道了钯催化的乙烯基膦酸二乙酯与各种芳基或杂芳基卤化物直接进行Heck芳基化反应以合成2-(芳基)乙烯基膦酸二乙酯的方法。在研究中使用了几种均相催化体系(即,Herrmann palladacycle,Nolan(NHC)-钯催化剂,Pd(OAc)2 / PPh 3)。无论使用何种均相催化剂,在最佳条件下(2摩尔%[Pd],NMP,K 2 CO 3和140°C)都可以实现高转化率和选择性。
Mechanosynthesis of phosphonocinnamic esters through solvent-free Horner-Wadsworth-Emmons reaction
yields (13–99%), from tetraethylmethylenediphosphonate, an aromatic or aliphatic aldehyde and potassium tert-butoxide, using 5 min of mortar and pestle grinding. Potassium tert-butoxide acts as a base and liquid-assisting grinding agent. All isolated products were fully characterized as (E)-isomers through NMR spectroscopy. Furthermore, among the synthesized compounds diethyl (E)-2-(4-methoxyphenyl)vinylphosphonate
摘要 在这里,我们报告了通过无溶剂机械活化的 Horner-Wadsworth-Emmons (HWE) 烯化,从亚甲基二膦酸四乙酯(一种芳香族或脂肪族醛)以常规至优异的产率(13-99%)温和合成 15 种膦酸肉桂酸酯和叔丁醇钾,用研钵和杵研磨 5 分钟。叔丁醇钾用作碱和助液研磨剂。所有分离的产物都通过 NMR 光谱完全表征为 ( E )-异构体。此外,在合成的化合物中,发现 ( E )-2-(4-甲氧基苯基)乙烯基膦酸二乙酯1是一种有趣的细胞毒剂,可抑制两种乳腺癌细胞系的生长 (MDA-MB-453, IC 50= 79 µg/mL 和 MCF-7 IC 50 = 64 µg/mL)。据我们所知,这是首次报道机械活化 HWE 反应用于合成 α、β-不饱和膦酸盐,并且其中一些首次被评估为对乳腺癌细胞系的细胞毒剂。总之,( E )-膦酸肉桂酸酯的快速且操作简单的合成提供了新的有前途的细胞毒
Pd-Catalyzed Sequential C–C Bond Formation and Cleavage: Evidence for an Unexpected Generation of Arylpalladium(II) Species
作者:So Won Youn、Byung Seok Kim、Arun R. Jagdale
DOI:10.1021/ja304616q
日期:2012.7.18
A Pd(II)-catalyzed reaction engaging alkenyl beta-keto esters is reported that leads to the formation of 1-naphthols and an unexpected generation of arylpalladium-(II) species. Interception of the in situ generated arylpalladium(II) species in a Mizoroki-Heck reaction, together with additional mechanistic studies, provided strong evidence in support of the first aromatization-driven beta-carbon elimination process. A single Pd catalyst served to promote a series of both C-C bond forming and cleavage events in an unprecedented manner.
Zhang, Yang-Hui; Shi, Bing-Feng; Yu, Jin-Quan, Journal of the American Chemical Society, 2009, vol. 131, p. 5072 - 5074
作者:Zhang, Yang-Hui、Shi, Bing-Feng、Yu, Jin-Quan
DOI:——
日期:——
Synthesis of diethyl 2-(aryl)vinylphosphonate by the Heck reaction catalysed by supported palladium catalysts
Interestingly, when using activatedaryl bromides the palladium loading could be lowered to only 0.25 mol%. While highlyactive when coupling aryl iodides (i.e. only 0.15 mol% required), the PdO/SiO2 catalyst was found to be inactive when considering aryl bromides. Deep study of this catalytic material revealed that in the case of aryl bromides, absence of in situ reduction of the catalyst precursor prevents