芳基碘化物和溴化物与丙烯醛二乙缩醛在Pd(OAc)(2),(n)()Bu(4)NOAc,K(2)CO(3),KCl和DMF存在下的反应,于90直至乙缩醛消失,然后向粗制反应混合物中加入2 N HCl,可以得到高至高收率的肉桂醛。芳基卤化物中可耐受多种官能团,包括醚,醛,酮,酯,二烷基氨基,腈基和硝基。靠近氧化加成位点的取代基的存在不妨碍反应。
Chemoselective Heck arylation of acrolein diethyl acetal catalyzed by an oxime-derived palladacycle
作者:Carmen Nájera、Luis Botella
DOI:10.1016/j.tet.2005.06.059
日期:2005.10
at 90 °C in aqueous DMA using (dicylohexyl)methylamine as base, whereas for bromoarenes the reaction has to be performed at 120 °C using tetra-n-butylammonium bromide (TBAB) as additive. Alternatively, this process can be performed under microwave irradiation. These couplings take place in good yields and with lower catalyst loading than with palladium(II) acetate as well as in shorter reaction times
甲二聚4-羟基苯乙酮肟衍生钯化合物已被用作一种非常有效的预催化剂用于通过反应条件的适当选择丙烯醛缩二乙醇,得到任一肉桂醛衍生物或3- arylpropanoate酯的化学选择性芳基化。肉桂醛衍生物的合成可以通过丙烯醛缩二乙醇与碘,在溴-或氯代芳烃的Heck反应进行Ñ,Ñ用k二甲基乙酰胺(DMA)2 CO 3作为在120℃下和四-碱Ñ-醋酸丁丁基铵(TBAA)和氯化钾作为添加剂,然后进行酸处理。对于3-芳基丙酸酯,相应的丙烯醛二乙缩醛与碘芳烃的芳基化反应可以在90°C的DMA水溶液中使用(二(己基己基)甲胺)碱进行,而溴芳烃的反应则必须在120°C的条件下使用四芳基进行。 -溴化正丁基铵(TBAB)作为添加剂。或者,该过程可以在微波辐射下进行。与乙酸钯(II)相比,这些偶联以高收率和较低的催化剂负载量发生,并且反应时间较短且丙烯醛二乙基缩醛过量的发生率较低。
Direct synthesis of 3-arylpropionic acids by tetraphosphine/palladium catalysed Heck reactions of aryl halides with acrolein ethylene acetal
作者:Mhamed Lemhadri、Henri Doucet、Maurice Santelli
DOI:10.1016/j.tet.2004.09.061
日期:2004.12
4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides undergoes Heck reaction with acrolein ethylene acetal. With this acetal, the selective formation of 3-arylpropionic acids/esters was observed. The functional group tolerance on the aryl halide is remarkable; substituents such as fluoro, methyl, methoxy, acetyl, formyl, benzoyl, nitro or nitrile are tolerated. Furthermore
An amine and bis(phenylsulfonyl)methane co-catalyzed hydrogen–deuterium exchange (HDE) method via a Michael-retro-Michael pathway for site-selective introduction of deuterium at the α-position of enals using D2O as a deuterium source has been achieved. The mild, operationally simple protocol allows for high yielding and high level deuterium incorporation (up to 99%) for structurally diverse aromatic-derived
一种胺和双(苯磺酰基)甲烷共催化氢-氘交换 (HDE) 方法,通过Michael-retro-Michael 途径,以 D 2 O 作为氘源,在烯醛的 α 位位点选择性引入氘。已达到。温和、操作简单的协议允许高产率和高水平的氘掺入(高达 99%),用于结构多样的芳烃衍生烯和二烯。