药明康德--钯催化的插羰反应-060410.doc

上传人:本田雅阁 文档编号:2747441 上传时间:2019-05-10 格式:DOC 页数:32 大小:1.42MB
返回 下载 相关 举报
药明康德--钯催化的插羰反应-060410.doc_第1页
第1页 / 共32页
药明康德--钯催化的插羰反应-060410.doc_第2页
第2页 / 共32页
药明康德--钯催化的插羰反应-060410.doc_第3页
第3页 / 共32页
药明康德--钯催化的插羰反应-060410.doc_第4页
第4页 / 共32页
药明康德--钯催化的插羰反应-060410.doc_第5页
第5页 / 共32页
点击查看更多>>
资源描述

《药明康德--钯催化的插羰反应-060410.doc》由会员分享,可在线阅读,更多相关《药明康德--钯催化的插羰反应-060410.doc(32页珍藏版)》请在三一文库上搜索。

1、经典合成反应标准操作钯催化的插羰反应 药明康德新药开发有限公司经典化学合成反应标准操作钯催化的插羰反应编者:钱占山药明康德新药开发有限公司化学合成部Contents1 前言2-32 插羰反应制备羧酸及其衍生物4-153 插羰反应制备羧酸实验操作15-164 插羰反应制备羧酸酯实验操作16-195 插羰反应制备酰胺实验操作19-206 插羰反应制备醛207 插羰反应制备醛实验操作21-228 插羰反应制备酮22-309 插羰反应制备酮实验操作30-311. 前言在有机合成中,钯催化的反应是一类特别有用的反应,它提供了一种形成碳-碳键的独特的方法。这类反应的优点:1、不需要加入其他氧化剂催化;2、

2、只需催化量的钯催化剂。钯催化的插羰反应是这类反应中应用最为广泛的反应之一,在这里我们将重点介绍它。众所周知,在格氏反应中单质镁金属与带有sp3杂化碳原子的有机卤化物(烷基卤化物)反应要比带有sp2杂化碳原子的有机卤化物(芳基和烯基卤化物)反应更容易。而与此相反,钯的络合物与含有sp2杂化碳原子的有机卤化物反应更容易。换句话说,烯基和芳基卤化物非常容易与Pd(0)发生氧化加成反应,从而生成含有钯-碳-键的络合物中间体1;然后,不饱和化合物(例如:烯烃、共轭二烯、炔烃和一氧化碳等)插入到钯-碳键之间;最后,经过还原消去或者-氢消去反应生成相应的目标化合物。与此同时,Pd(0)催化剂得以再生并开始新

3、的催化循环。由此可见,正是因为生成了这种含有钯-碳-键的络合物中间体,才使得接下来的插入和金属转移过程变成可能。实验证明,Pd的配合物比较容易与碘化物和溴化物发生氧化加成反应。碘化物可以在不加入任何膦配体的条件下,只用Pd(dba)3、Pd(OAc)2甚至是Pd/C作催化剂即可发生反应。而溴化物的反应一般是需要膦配体的。但是氯化物在一般的条件下是非常惰性的,只有用较强给电子性的具有双配位基(bidentate)的配体(如dppp),同时在非常剧烈的条件下才能发生反应。例如氯苯的钯催化反应往往要加入Cr(CO)3,目的是利用它的强吸电子性活化Cl-C键。应该指出的是,为了中和反应生成的HX酸,碱

4、(R3N、NaOAc、KOAc、Na2CO3、K2CO3等)的使用是必需的。除了卤化物以外,类卤化物R-X = ArCO-Cl, ArSO2-Cl, Ar-N2+X-, R-OP(O)(OR)2, R-OSO2CF3 (OTf), R-OSO2Rf (Rf = perfluoroaikyl), R-OSO2F, R-OSO2CH3和Ar-ArI+是很好的离去基团,它们也能与Pd(0)发生氧化加成反应从而形成芳基和烯基钯配合物中间体。但是,这些离去基团对于Pd(0)的反应活性是各不相同的,它们中的某些化合物往往只能和某些特定的底物在非常特殊条件下发生反应。最有用的类卤化物是酚的三氟甲磺酸芳基酯和

5、从羰基化合物派生出来的三氟甲磺酸烯醇酯。芳酰基卤化物和磺酰基卤化物通过先与Pd(0)发生氧化加成反应,紧接着脱去CO和SO2就形成了芳基钯配合物。另外,苯的重氮盐是形成芳基钯配合物的最活泼反应源。烷基卤化物和Pd(0)的氧化加成反应是非常缓慢的。而且,通过烷基卤化物的氧化加成反应得到的烷基钯配合物经过-氢消除之后,反应就停止在这一阶段,而不再进行插入或金属转移过程。对于炔基卤化物来说,虽然没有太多的文献报道,但是炔基碘化物的确可以和Pd(0)反应生成炔基钯配合物。2. 插羰反应制备羧酸及其衍生物芳基和烯基卤化物在温和条件下的钯催化插羰反应是合成羰基化合物的非常有用的合成方法。反应机理是芳基和烯

6、基卤化物先和Pd(0)发生氧化加成反应生成芳基或烯基钯配合物,然后CO插入到钯-碳键之间,最后在醇或水等试剂的亲和进攻下就形成了相应的酯或羧酸。芳香的或,不饱和的羧酸或酯就是芳基或烯基卤化物在水或醇中通过插羰反应制得的。在玉米烯酮2-4的全合成中,酯2-3是通过基团密集的芳基碘化物2-1的插羰反应制得的。然而醇分子2-2中的烷基碘部分是不参与反应的。三氟甲基丙烯酸甲酯2-6 被制备是通过3,3,3-三氟-2-溴丙烯的插羰反应。这个羰基化反应在烷基尿素存在下就生成化合物2-7,它可以进一步被转化成三氟甲基尿嘧啶2-8。这是个非常有价值的反应。在通常情况下,碘化物和溴化物常被用于插羰反应,而氯化物

7、是非常惰性的。但是,在使用双配位基膦(bidentate phosphine)的条件下,芳基氯化物的氧化加成反应可以顺利进行。因为双配位基膦可以和钯形成一个六元环螯合物结构,这样就增强了钯的电子云密度。举个例子,苯甲酸可以通过氯苯的羰基化反应合成,但是这个反应必须要用bis(diisopropylphosphine)propane 2-9(dippp)作为配体,在150oC高温条件下进行。另外,tricyclohexylphosphine被用于芳基卤化物在氢氧化钾水溶液等两相条件下的插羰反应也是可取的。碘苯的衍生物在H2O/DMF(1:1)的混合溶剂中,不加任何膦配体在室温和1atm压力下就可

8、以进行插羰反应生成苯甲酸的衍生物2-10。在利用插羰反应合成邻氨基苯甲酸衍生物2-10的过程中发现,反应物邻溴苯胺衍生物上的氨基被乙酰基保护对插羰反应是至关重要,这也许是螯合效应的缘故。在卤化物的插羰反应中,有时需要钯催化剂和相转移催化剂合用来催化反应。1,1-二溴烯烃2-12在相转移催化剂BnNEt3Cl的作用下成功的合成出不饱和二羧酸2-13。在此反应中,极性溶剂的使用是非常重要。醇2-14用Pd(OAc)2和Ph3P作催化剂在甲苯溶剂中插羰可以得到内酯2-15。有趣的是,在此反应中加入Me3SiCl(2 equiv.)可以非常明显提高反应收率。甲酸酯可以代替CO作为插羰反应的羰基源,它常

9、和NaOR一起用于插羰反应。碘苯在氮气保护下,用PdCl2(Ph3P)2作催化剂,与甲酸甲酯和甲醇钠反应制得苯甲酸甲酯。氯苯在Cr(CO)3活化下可以与甲酸乙酯发生插羰反应。苄氯插羰可以得到苯乙酸酯。苄氯在两相溶剂(水和庚烷)中用水溶性的磺化的膦化物作为配体(water-soluble sulfonated phosphine,DPMSPP)通过插羰反应以较高的收率(89%)制得苯乙酸2-16。在一个大气压下,通过用triethylbenzylammonium chloride作为相转移催化剂,苄氯和叔丁醇插羰反应可以制备苯乙酸叔丁酯。苄基卤化物的插羰反应还可以在中性的的条件下进行,例如使用分

10、子筛、四甲基尿素等。在大环内酯弯孢霉菌素2-20的全合成中,酯2-19的制备就是在这种中性的条件下通过苄基氯化物的钯催化插羰反应而获得的。虽然绝大多数的醋酸苄酯不能应用于插羰反应,但是手性化合物1-和2-(1-acetoxymethy)naphthalenes 2-21可以进行插羰反应的,它在HCO2Na和dppp的条件下通过formate-mediated carbonylation得到羧酸2-22和2-23(84:16)。同样,相应的1-naphthylethyl formate也能进行插羰反应。苯乙酸衍生物2-25也可以由带有给电子基团的芳香醛2-24通过插羰反应获得。这个反应要在110

11、oC,50-100 atm(CO)压力和Pd-Ph3P-HCl的催化体系中进行。此反应的可能机理如下所示:三氟甲磺酸苯酚酯用Ph3P作为配体插羰可以制得芳香酸酯。如果这个反应改用dppp作为配体,反应速度可以提高500倍。这个反应是由苯酚制备苯甲酸酯和由萘酚制备萘甲酸酯2-26的非常好的方法。轴手性化合物1,1-联萘-2,2-二酚的三氟甲磺酸酯 2-27用dppp作为配体插羰可得单羧酸酯2-28。而光学纯二羧酸酯2-29在类似的条件也能得到,但必须要用4.4倍量的受阻胺(hindered amine),例如ethyldiisopropylamine;这种胺的用量对于二羰基化反应来说是至关重要的

12、,多于或少于4.4倍量都会得到单酯2-28。由醛或酮派生的三氟甲磺酸烯醇酯通过插羰反应可以得到,-不饱和酯。甾族酯可以从他们相应的三氟甲磺酸芳香酯和烯醇酯制得。在下列化合物2-30中,三氟甲磺酸烯醇酯要比三氟甲磺酸芳香酯反应活性更高,因此这个插羰反应是逐步进行的。首先,三氟甲磺酸烯醇酯插羰得到胺2-31;然后,在DMSO中用dppp作配体进行第二次插羰得到酯2-32。通过插羰反应制备羧酸是在水中进行的。对于enol triflate和aryl triflate的羰基化反应来说,选择反应溶剂是至关重要的。Enol triflate 2-33的插羰反应制备羧酸要在水和DMF的混合溶剂中才得以进行。

13、Aryl triflate 2-34的羰基化反应要在水和DMSO的混合溶剂中进行,并要用dppp作配体。由enol triflate 2-35制备,-不饱和羧酸2-36是用dppf作配体在水和DMF的混合溶剂中进行的。非常有意思的是,在碱性条件下,碘苯可以和氯仿反应生成苯甲酸,此反应无需CO参与。其他的类卤化物也可以用于插羰反应。Phenyl fluorosulfonate 2-37插羰可得苯甲酸酯。Aryl(alkenyl)iodonium salts、aryl(alkenyl)iodonium salts 2-38和aryl(alkynyl)iodonium salts 2-39时活性非常

14、高化合物,他们在比较温和的条件(室温, 1 atm)下就可以插羰生成芳基、烯基和炔基酯。Iodoxybenzene 2-40在1atm,40oC的水溶剂中就可以发生插羰反应得到苯甲酸。另外,苯甲酸的衍生物也可以通过芳基重氮盐在温和条件下插羰反应制备。例如,苯基重氮盐2-41在醋酸中插羰可得混合酸酐2-41。利用这个方法,硝基苯可以间接转化成苯甲酸。在CsF存在下,芳基卤化物能够极其温和的条件下进行插羰反应,并以较高收率得到酰基氟化物2-43。与酰氯不同,酰氟对于钯催化剂来说是惰性的。苯磺酰氯2-44在160oC和titanium tetralkoxide存在下,经过脱磺酸基和插羰反应可以得到苯

15、甲酸酯2-45。杂芳环溴化物通过插羰反应可以生成杂芳基酯(例如:2-46)和杂芳酰胺。甚至二氯吡嗪2-47和氯吡啶在比较苛刻的条件(120 oC, 40 atm)下都可以进行插羰反应。Trifluoroacetimidoyl iodides 2-48 在温和条件下的插羰反应可以被用来合成三氟甲基甘氨酸的衍生物2-49和2-50。在1 atm压力,伯胺或仲胺存在的情况下,卤化物的插羰反应生成酰胺。带有氨基的芳基溴化物的分子内羰基化反应可以得到内酰胺,这个方法已经被应用于异喹啉生物碱2-51的合成。天然七元环内酯2-52(tomaymycin, neothramycin)的合成也是通过这个方法。-

16、烯基-内酯2-53的形成也是通过2-溴-3-烷氨基-1-丙烯的分子内羰基化反应。邻二碘苯和伯胺的插羰反应可以生成邻苯二甲酰亚胺2-54。在DBU或2,6-二甲基吡啶存在下,碘苯和邻苯二胺的插羰反应得到2-苯基苯并咪唑2-56。手性的aryl或alkenyl oxazoline 2-59被制备是通过aryl或enol triflates在手性氨基醇2-57存在下先进行插羰反应得到酰胺2-58,然后再在SOCl2中脱水关环。对于插羰反应来说,烯基氯化物一般是非常不活波的,但是氯乙烯是个例外,它可以和NH3在100oC发生插羰反应生成迈克尔加成产物酰胺2-60,这个反应的收率非常高。在一定条件下,卤

17、化物还可以进行两次插羰反应,从而生成-酮酸的衍生物。它是单羰基化反应的竞争反应。用Ca(OH)2作碱,烷基膦作配体,碘苯在水中插羰生成-酮酸(苯基乙醛酸)2-61。同样,在水和异丙醇的混合溶剂中,Ca(OH)2作碱,Me3P作配体,碘苯经过两次插羰和还原之后得到苦杏仁酸2-62。另外,碘苯和二级胺在用烷基膦或双齿膦作配体的条件下经过二次插羰反应生成-酮酰胺2-63,此反应的化学选择性非常高。邻碘苯胺衍生物的二次插羰产物可以转化成靛红2-65和喹啉2-64。氯苯在Cr(CO)3作用下,用PdCl2(MePh2P)2作催化剂经过两次插羰反应生成-酮酰胺和苯甲酰胺。-酮酯2-67能够通过碘苯和大位阻

18、二级胺的二次羰基化反应形成,但是这个反应的选择性非常低。对于二次插羰反应来说,烯基溴化物比芳基卤化物的反应活性更低。-酮酰胺能够通过芳基和烯基溴化物的二次羰基化反应得到,而-酮酯是不能够通过他们在相应醇中的羰基化反应得到。3. 插羰反应制备羧酸实验操作A 200-mL glass pressure bottle equipped with two valves and a pressure gauge was charged with 8 mg of Pd(PPh3)(Cl)2, 40 mg of triphenylphosphme, and 2.0 g of 2-(acetylamino)-

19、5-(1-methylethyl) phenylbromide. The bottle was then evacuated, refilled with argon three times, and charged further with 2.2 mL of deoxygenated tri-n-butylamine and 0.5 mL of deoxygenated water. The apparatus was then pressurized with 3 atm of carbon monoxide, sealed, heated 18 h with stirring at a

20、 bath temperature of 120-125 C, and then allowed to cool. The final pressure was 1.1 atm at 23 C. Hydrochloric acid (2.4 M) was added to the viscous orange-brown reaction mixture in four 2-mL portions with constant agitation. The crude yield of 2-11 which separated (95% pure by NMR) was 1.63 g (94%)

21、. Recrystallization from ethanol-water gave 1.35 g (78%) of a light yellow solid.4. 插羰反应制备羧酸酯实验操作A mixture of the iodobenzene 2-1 (0.46 mmol), w-indo alcohol 2-2 (0.83 mmol), K2CO3 (1.38 mmol), and PdCl2 (0.04 mmol) in dry benzene (6 mL) was heated at 120 with stirring in an autoclave under carbon m

22、onoxide (12 atm) for 16 h. The reaction mixture was filtered and the easter 3 was isolated by column chromatography in 70% yield.(2R,4S)-4-3,5-Bis(trifluoromethyl)benzyl-(5-bromopyrimidin-2-yl)-amino-2-ethyl-6-methoxy-3,4-dihyfro-2H-1,5naphthridine-1-carboxylic acid ethyl ester (18 g) is dissolved i

23、n N,N-dimethylformamide (60 mL), and thereto are added palladium acetate (611 mg), 1,1-bis(diphenylphosphino)-ferrocene (3.02 g), ethane (31.7 mL) and triethylamine (37.9 mL). The mixture is purged by carbon monoxide at room temperature for 10 minutes, then is heated at 90 oC and stirred overnight u

24、nder 40 psi of carbon monoxide. The reaction solution is cooled to room temperature, and thereto is added saturated brine and extracted with ethyl acetate. The organic layer is washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The resulting residue i

25、s purified by column chromatography (silica gel; hexane:ethyl acetate = 8:1) to give (2R.4S)-4-3,5-bis(triflouromethyl)benzyl-(5-ethoxycarbonylpyrimidin-2-yl)amino-2-ethyl-6-methoxy-3,4-dihydro-2H-1,5naphthyridine-1-carboxylic acid ethyl ester (12.4 g).To a stirred solution of 3-(aminocarbonyl)-4-3-

26、(methyloxay)penylamino-6-iodoquinoline (1 g) in ethanol (50 mL) was added triethylamine (0.63 mL) and dichlorobis(triphenylphosphine)palladium (II) (0.08 g). The flask was evacuated and refilled with nitrogen three times and then evacuated and refilled with carbon monoxide two times. The mixture was

27、 heated at 80oC under an atmosphere of carbon monoxide for 16 h. the mixture was cooled to 20oC and the solvent removed in vacuo. Purification by column chromatography on silica gel, eluting with 9:1 ethyl acetate: cyclohexane, gave the title compound as a pale yellow solid (0.8 g).6-bromo-4-2-(6-me

28、thyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo1,2-Bpyrazol-3-yl-quinoline (22.7 g, 45 mmol) is added to a mixture of sodium acetate (19 g, 230 mmol) and the palladium catalyst 1,1-bis (diphenylphosphimo) ferrocene dichloropalladium (II) complex with dichloromethane (1:1) (850 mg, 1.04 mmol) in 130 mL met

29、hanol. Place the mixture under 50 psi carbon monoxide atmosphere and stir while warming to 90oC over 1 hour and with constant charging with additional carbon monoxide. Allow the mixture to cool over 8 hours, recharge again with carbon monoxide and heat to 90oC. The pressure may rise to about 75 psi.

30、 The reaction is complete in about an hour when the pressure is stable and TLC (1:1 toluene/acetaone) shows no remaining bromide. Partition the mixture between methylene chloride (600 mL) and water (1 L). Extract the aqueous portion with an additional portion of methylene chloride (400 mL). Filter t

31、he organic solution through a 300 mL silica plug and wash with 500 mL methylene chloride, 1200 mL ethyl acetate and 1500 mL acetone. Discard the acetone portion. Combine appropriate fractions and concentrate to yield 18.8 g (87.4%) of the desired subtitled intermediate as a pink powder.A solution of

32、 N-(4-chlorobenzyl)-4-hydroxy-6-iodo-3-quinolinecarboxamide (30.0 g), Et3N (19.1 mL), MeOH (110.6 mL), Pd(OAc)2 (431 mg), and 1,3-bis(diphenylphosphino)propane (791.9 mg) in 375 mL anhydrous DMF is stirred at room temperature until everything dissolves. CO (g) is slowly bubbled through for 2 days an

33、d the reaction is maintained at 70oC. The reaction is cooled to room temperature. The product is precipitated by adding 160 mL 1 N HCl into the reaction mixture. An orange solid precipitates is collected. The solid is triturated with EtOAc, filtered, and washed with CH2Cl2 to afford 23.8 g (93 % yie

34、ld) of the title compound as an off-white solid.A mixture of 2-(3-iodo-2-methyl-phenyl)-pyrrolidine-1-carboxylic acid tert-butyl ester (26 g, 0.067 mol), Pd(PPh3)4 (2.4 g, 0.002 mol), Et3N (14.3 mL, 0.1 mol), 110 mL of acetonitrile and 50 mL of methanol was stirred under 50 Psi of carbon monoxide at

35、 50 C for 8 h. The reaction mixture was filtered and concentrated in vacuo. The residue was dissolved in 250 mL of ethyl acetate, then washed with water and brine, dried over anhydrous sodium sulfate and concentrated in vacuo to give crude product, which was purified by column chromatography (petrol

36、eum ether: ethyl acetate 30:1 to 10:1) to afford the title product (20 g, 93%) as a gray solid.PdCl2 (18.4 g, 0.104 mol) and BINAP (27.6 g, 0.044 mol) were added to a solution of 5-(2-bromo-phenyl)-oxazole (331.0 g, 0.44 mol) and Et3N (242.2 g, 2.22 mol) in 6 L CH3OH/CH3CN (2:1) in steel bomb. The m

37、ixture was stirred at 100 C under CO (1 atm) for 48 h. The mixture was filtered and the filtrate was evaporated. The residue was purified by column chromatography (EtOAc/petroleum = 1:10) to give 2-oxazol-5-yl-benzoic acid methyl ester (210.0 g, 70 %) as brown oil.5. 插羰反应制备酰胺实验操作A mixture of 2-52-A

38、(6.3 mg, 11 rmnol), Pd(PPh3)4 (1.27 g, 1.1 mmol) and n-Bu3N (4.47 g, 24.2 mmol) in toluene (20 mL) was heated under carbon monoxide(10 atm) at 1l0oC for 24 h. Ethyl acetate was added to the reaction mixture and the organic layer was washed with 5% HCl, 5% Na2S2O3, sat. NaHCO3 and then brine, dried o

39、ver Na2SO4 and evaporated. The residue was purified by column chromatography ethy1 acetate-CH2Cl2 (1:l). The second fraction was 2-52 (3.93 g, 69 %).6. 插羰反应制备醛醛可以通过卤化物在不同氢源中的钯催化的插羰反应制备。芳基和烯基碘化物和溴化物在惰性溶剂中,三级胺存在的条件下与CO和H2(1:1)发生插羰反应生成醛。而芳基氯化物要先生成碳酸铬的衍生物后,才能在130oC的温度下转化成醛。甲酸钠可以代替H2被用作氢源来合成醛。氯苯在150oC的温度

40、下,用dippp作为配体,与CO和甲酸钠反应制得苯甲醛。用锡的氢化物作为氢源,Pd(Ph3P)4作为催化剂,芳基、烯基卤化物或三氟甲磺酸酯和苄基、烯丙基氯化物的羰基反应也能制备醛。硅的氢化物也能被用作氢源。重氮盐6-1通过用Et3SiH或PHMS作为氢源,可以高收率快速的转化成邻甲基苯甲醛。7. 插羰反应制备醛实验操作To the 45 mL-Parr bombwere added 3.95 g (25.0 mmol) of 3-bromopyridine, 10 mL of triethylamine, 10 mL of benzene, and 0.30 g (0.375 mmol) of

41、 dibromobis(triphenylphosphine)palladium (II). The bomb was then flushed with argon, sealed, and pressurized to 600 Psi with carbon monoxide. After the pressure was released, the bomb was re-pressurized to 600 Psi with carbon monoxide and finally pressurized to 1200 Psi with hydrogen. The reaction v

42、essel was heated in an oil bath with stirring at 145oC. After 20 min, the pressure reached a maximum of 1350 Psi. Times and pressure were periodically recorded until gas absorption stopped (26 hr), and the pressure in the reaction vessel had decreased to 1025 Psi. The reaction vessel was cooled, and

43、 the gases were slowly released. After addition of anhydrous ether, the reaction mixture was filtered to remove the triethylamine hydrochloride, concentrated in vacuo to remove ether, benzene, and triethylamine, and finally distilled to give 2.15 g of (80% yield) of product.The 75-mLreaction bomb wa

44、s charged with 5.9 g (25.0 mmol) of 1,4-dibromobenzene, 11.2 g (60.0 mmol) of tri-n-butylamine, 15 mLof benzene, and 0.4 g (0.5 mmol) of dibromobis(triphenylphosphine)palladium (II). The bomb was then flushed with argon, sealed, and pressurized to 600 Psi with carbon monoxide. After the pressure was

45、 released, the bomb was re-pressurized to 600 Psi with carbon monoxide and finally pressurized to 1200 Psi with hydrogen. After 15 min, the pressure reached 1375 Psi at 140oC and decreased to 600 Psi after 24 hr of treaction. The vessel was then cooled to room temperature and the pressure released.

46、After addition of anhydrous ether, the reaction mixture was filtered to remove the triethylamine hydrochloride, concentrated in vacuo to remove ether, benzene, and triethylamine. After evaporation of the ether, the resulting solids were sublimed (100oC, 8 mm) to give 3.79 g of a mixture of the terep

47、hthalaldehyde and 1,4-dibromobenzene. The mixture was separated by chromatography on silica gel. There were obtained 0.66 g (2.8 mmol) of 1,4-dibromobenzene and 2.47 g (18.4 mmol) of 1,4-benzenedicarboxaldehyde (83% yield). Recrystallization from hexane yielded 2.21 g of pure dialdehyde.8. 插羰反应制备酮在Zn, B, Al, Sn, Si, Hg等有机金属化合物或其他亲核试剂(他们可以进攻酰基钯中间体,发生金属转移和还原消去反应)的存在下,卤化物和类卤化物的羰基化反应可以生成酮。芳基碘化物在烷基碘化物和Zn-Cu存在条件下发生插羰反应,以非常高的收率生成了烷基芳基酮。这个反应首先生成烷基锌试

展开阅读全文
相关资源
猜你喜欢
相关搜索

当前位置:首页 > 其他


经营许可证编号:宁ICP备18001539号-1