超声条件下单取代芳基硼酸的合成研究

在超声条件下,以碘为催化剂,利用硼酸酯与卤代芳烃、金属镁粉合成了4种单取代芳基硼酸.确定了反应的最佳工艺条件:在碘的催化作用下,超声波功率170 W,反应温度46℃,反应时间30min,产物收率79%～86%.研究表明,随着硼酸酯取代基空间结构的增大,收率也会提高.产品经1HNMR、IR进行了确认.     

芳基硼酸在有机合成中的应用

芳基硼酸作为一种重要的中间体,在有机合成中的应用相当广泛。Suzuki偶联反应是合成联芳基结构最有效的方法之一,近年许多用于芳基硼酸与各种卤代芳烃偶合的催化剂相继被开发。芳基硼酸与苯酚在Cu(OAc)2和NEt3存在时用于合成二芳基醚,与胺的偶联是合成C-N键的有效方法,与,α-β不饱和体系的1,4-共轭加成反应广泛用于β-取代羰基化合物的合成。反应采用相对无毒而又廉价的普通试剂,反应条件温和,产率高,立体选择性好。综述了芳基硼酸在联芳基合成、二芳基醚合成、芳香胺合成和催化加成反应中的应用。     

1-芳基-3-芳甲酰基中氮茚的合成

合成了九个1-芳基中氮茚衍生物。首先由取代苯乙酮,碘,乙酸和吡啶四组分一锅煮反应合成中间体1-碘代中氮茚,然后在钯催化剂作用下,使用制得的的1-碘代中氮茚和芳基硼酸的Suzuki偶联反应合成得到目标化合物,所合成化合物结构通过红外,核磁及质谱进行了表征。     

1-甲基-1H-苯并咪唑-4-硼酸的合成

以1-溴-3-氟-2-硝基苯为原料,经甲胺取代,锌粉还原,甲酸环化3步反应合成4-溴-1-甲基-1H-苯并咪唑,再与频哪醇硼酸酯在双(三环己基膦)二氯化钯催化下进行硼酸化,制得未见文献报道的目标化合物1-甲基-1H-苯并咪唑-4-硼酸,4步反应总收率27.4%。产品经MS和1H NMR确证。该合成工艺具有反应条件温和、操作简单的优点。     

双水相体系中Pd/C催化Suzuki偶联反应的研究

以双水相为反应溶剂,用可重复使用的Pd/C为催化剂,在较低的温度下(78~85 ℃),芳基硼酸与芳基卤化物进行了Suzuki反应.该方法具有反应时间短、产率较高、选择性较好等特点,为该反应及该类化合物的合成提供了一种新方法.产物通过熔点测定,核磁共振氢谱、碳谱、质谱等的表征.     

废芳基硼酸类化合物的回收利用

为了提高芳基硼酸化合物的收率,减少芳基硼酸制备过程中含硼酸副产物对环境的污染,开发出了芳基硼酸化合物的脱硼酸技术,以4’-乙基-4-苯基-2-氟苯硼酸(Ⅰ)脱除硼酸基团为例,在碱性条件下,于60~68℃反应,得到了(Ⅰ)的初始原料4’-乙基-4-苯基-2-氟苯,收率87%。并对4’-乙基-4-苯基-2-氟苯的结构进行了质谱确认,对芳基硼酸化合物脱硼酸的机理给出了推测,利用此技术可以回收有用原材料,减少芳基硼酸生产中的废物排放量。     

聚乙二醇中咪唑与芳基硼酸的N-芳基化反应

N-芳基咪唑类化合物是一类非常重要的结构单元,常见于药物、农药以及生物分子中,因此寻找新的合成N-芳基咪唑类物质的方法成为有机合成化学家关注的热点问题之一。在绿色化学的倡导下,研究发展了一个促进咪唑类底物与芳基硼酸N-芳基化反应的催化体系,它是以Cu_2O(10%)为催化剂,以聚乙二醇400为反应介质,在室温下反应。研究结果表明,该催化体系适用于咪唑类底物与各种具有不同取代基的芳基硼酸的N-芳基化反应,为N-芳基咪唑类化合物提供一个简单、有效、绿色的合成方法。     

3-芳基香豆素及其衍生物的研究进展

3-芳基香豆素及其系列衍生物因具有重要的生物、医药活性及良好的光学性能而受到人们的广泛关注.本文概述了近年来3-芳基香豆素及其衍生物的主要合成方法,并介绍了这些方法在合成中的优缺点,为3-芳基香豆素的进一步合成研究提供依据.     

3′,4′,5′-三氟联苯-4-硼酸的合成及表征

使用工业上易得的原料通过3步反应合成标题化合物.苯硼酸与3,4,5-三氟溴苯作为起始原料,在K2CO3水溶液和甲苯体系中,Pd/C催化反应生成3,4,5-三氟联苯,产率80%.接着3,4,5-三氟联苯在CCl4中经过Fe+I2催化溴化得到4′-溴-3,4,5-三氟联苯,产率75%.4′-溴-3,4,5-三氟联苯与n-BuLi在-78 ℃下反应生成3′,4′,5′-三氟联苯-4-锂,然后与硼酸三正丁酯-78 ℃反应,最后在室温下酸性条件下水解生成目标产物,产率86%.合成路线的总收率达到51.6%.合成的化合物用元素分析、FT-IR、1HNMR和13CNMR等手段进行了表征.     

芳基硼酸衍生物的阻燃性能

为了扩展芳基硼酸衍生物的应用领域,探索其作为有机阻燃剂的应用,设计并合成了一种新型芳基硼酸衍生物:三(4,4',4″-三硼酸-苯基)胺(3BzN-3B)。利用热重曲线和差示扫描量热曲线研究了3BzN-3B的热性能,研究结果发现3BzN-3B有较好的成炭性和较高的残炭率,其残炭率为49.1%,可作为一种有机阻燃剂使用。进一步利用热重曲线和扫描电镜研究了3BzN-3B对环氧树脂的阻燃性能,研究结果发现,随着3BzN-3B含量的增加,环氧树脂的残炭率逐渐增加,表明3BzN-3B在升温过程中,有促进环氧树脂成炭的作用。3BzN-3B是一种新型有机阻燃剂。     

Electron‐Poor,Fluoro‐Containing Arylboronic Acids as Efficient Coupling Partners for Bis(1,5‐cyclooctadiene)nickel(0)/Tricyclohexylphosphine‐Catalyzed Cross‐Coupling Reactions of Aryl Arenesulfonates

The use of electron‐poor, fluoro‐containing arylboronic acids as general coupling partners for nickel(0)/tricyclohexylphosphine‐catalyzed cross‐coupling of aryl arenesulfonates is described. Electron‐poor fluoro‐containing arylboronic acids were found to react faster than electron‐rich/neutral arylboronic acids, with (4‐methoxyphenyl)(4‐methylbenzenesulfonato‐κO)bis(tricyclohexylphosphine)nickel. Bis(1,5‐cyclooctadiene)nickel(0)/tricyclohexylphosphine, (4‐methoxyphenyl)(4‐methylbenzenesulfonato‐κO)bis(tricyclohexylphosphine)nickel and bis(tricyclohexylphosphine)nickel(II) bromide were all found to be efficient catalysts/catalyst precursors.

     

Palladium(II)‐Catalyzed Regio‐ and Stereoselective Hydroarylation of Diphenylphosphorylallenes with Arylboronic Acids in the Presence of Sodium Hydroxide and Oxygen

The palladium(II)‐catalyzed hydroarylation of diphenylphosphorylallenes (via 1,2‐addition of the allenic double bond) with arylboronic acids in the presence of sodium hydroxide and oxygen is developed. The regioselectivities turn out to be well controlled, affording 2‐aryl‐3‐(diphenylphosphinyl)alkenes as the only product. Moreover, the stereoselectivities for reactions of γ‐substituted allenes can also be nicely controlled, resulting in the formation of Z‐alkenes. The reaction shows high substituent loading capability and tolerance of various substituents. A mechanism, including transmetalation of arylboronic acid with palladium halides, insertion of the 1,2‐allenic double bond to the Pd−Ar bond, and protonation to afford the final hydroarylation product is proposed.

     

多环芳烃类单取代硼酸的合成研究

报道了多环芳烃类单取代硼酸的“一锅”合成新方法。选择BF3·OEt2 作为硼化试剂 ,与多环溴代芳烃、Mg粉 (物质的量比 1∶1∶1 )在 35℃“一锅”反应 5h来制备单取代硼酸 ,可以获得40 %～ 60 %的产率 ,产物质量分数为 98%～ 99%。考察了溶剂、硼化试剂、温度对反应的影响 ,发现选用乙醚做溶剂、BF3·OEt2 做硼化试剂在回流温度下反应能够顺利进行 ,并对亲核反应机理作了探讨。产物用液相色谱、红外、核磁进行了分析和结构鉴定。     

钯催化反应合成噻唑类化合物

以Pd（PPh3）4为催化剂,以2-溴噻唑和连有不同取代基团的苯硼酸为原料合成了系列芳基噻唑偶联化合物,考察了多种溶剂、不同种类碱和催化剂比例等反应条件的变化对产品收率的影响,并通过单因素法优化了芳基噻唑偶联反应的条件。同时研究了芳基硼酸上连有不同取代基时,对反应收率的影响,并总结其反应规律。     

Oxidative cyanide-free cyanation on arylboronic acid derivatives using aryl/heteroaryl thiocyanate using novel IL-PdCl4 catalyst under mild condition

An efficient and simple method is reported for the cyanation on arylboronic acid using various simple/indole thiocyanates using a new IL-PdCl₄ catalyst. The cascade process involves a coupling reaction without any additive to give a wide range of cyanide derivatives. Cyanation on various arylboronic acids underwent smoothly affording the corresponding arylnitriles in good to high yields.     

New Electrosynthesis of Arylboronic Esters from Aromatic Halides and Pinacolborane

A novel synthesis of arylboronic esters by a reductive electrochemical coupling reaction between aromatic halides and pinacolborane (HBpin, pin=pinacolate) has been carried out leading to arylboronic esters in moderate to good yields.     

Synthesis of 3‐Arylindole‐2‐carboxylates via Copper‐Catalyzed Hydroarylation of o‐Nitrophenyl‐Substituted Alkynoates and Subsequent Cadogan Cyclization

A two‐step route to biologically important 3‐arylindole‐2‐carboxylic esters has been successfully established: o‐nitrophenyl‐substituted alkynoates underwent copper‐catalyzed hydroarylation in the presence of commercially available arylboronic acids to afford 3,3‐diarylacrylates, which were then converted to indolecarboxylates via a modified Cadogan cyclization using a molybdenum catalyst and triphenylphosphine.     

Palladium‐Catalyzed Heck‐Type Reactions of Allylic Esters with Arylboronic Acids or Potassium Aryltrifluoroborates

A selective and general route to (E)‐1,3‐diaryl‐prop‐1‐enes and (E)‐3‐arylallyl acetates has been developed by palladium‐catalyzed Heck‐type reactions of allylic esters with arylboronic acids or potassium aryltrifluoroborates. The present method selectively proceeds including β‐OAc elimination or β‐H elimination on the basis of the boronic acids. Whereas a variety of allylic esters were reacted with arylboronic acids, palladium(II) acetate [Pd(OAc)₂], tetra(n‐butyl)ammonium chloride [(n‐Bu)₄NCl] and postassium dihydrogen phosphate (KH₂PO₄) to afford the corresponding diarylation products in moderate to good yields, treatment of allylic esters with potassium aryltrifluoroborates furnished the corresponding monoarylation products.