Highly diastereoselective vinylogous Mukaiyama aldol reaction of α-keto phosphonates with 2-(trimethylsilyloxy)furan catalyzed by Cu(OTf)2

The diastereospecific formation of δ-hydroxyalkylbutenolide phosphonate has been achieved via a vinylogous Mukaiyama aldol reaction. The reaction was performed using α-ketophosphonate 1 and 2-(trimethylsilyloxy)furan 2 mediated by Cu(OTf)(2) and 2,2,2-trifluoroethanol as additive in CH(2)Cl(2). The reaction proceeds rapidly and affords the corresponding 5-(hydroxy(aryl)methyl) furan-2(5H)-one phosphonates 3 in high yields with good to excellent diastereoselectivities (d.r. up to >99?:?1). 5-(Hydroxy(alkyl)methyl)furan-2(5H)-one phosphonates could also be obtained with good diastereoselectivities.     

Methyl 2-methoxytetrafluoropropionate as a synthetic equivalent of methyl trifluoropyruvate in the Claisen condensation. The first synthesis of 2-(trifluoroacetyl)chromones and 5-aryl-2-hydroxy-2-(trifluoromethyl)furan-3(2H)-ones

2-(Trifluoroacetyl)chromones and 5-aryl-2-hydroxy-2-(trifluoromethyl)furan-3(2H)-ones were obtained in good yields via the Claisen condensation of acetophenones with methyl 2-methoxytetrafluoropropionate, followed by sulfuric acid-mediated deprotection of the reaction products.     

Preparation of 3,4,5-substituted furan-2(5H)-ones using aluminum hydrogen sulfate as an efficient catalyst

Various derivatives of 3,4,5-substituted furan-2(5H)-ones have been readily prepared by using aluminum hydrogen sulfate [Al(HSO₄)₃] as an efficient catalyst in good yields and milder reaction conditions. The versatility of this protocol has been demonstrated with various substituted furan-2(5H)-ones.     

CAN-promoted, diastereoselective synthesis of fused 2,3-dihydrofurans and their transformation into tetrahydroindoles

The reaction between 1,3-cyclohexanediones and chalcones (or their vinilogs) in the presence of 2.5 equiv of cerium(IV) ammonium nitrate afforded trans-2-arylcarbonyl-3-aryl (or styryl)-2,3,6,7-tetrahydrobenzofuran-4(5H)-ones in good to excellent yields and in high diastereoselectivities. The method was also extended to the preparation of derivatives of the 5,6-dihydro-2H-cyclopenta[b]furan-4(3H)-one system. The fused 2,3-dihydrofuran derivatives were transformed into 1-alkyl-2-acyl-3-aryl-6,7-dihydroindole-4(5H)-ones by 2,3-dehydrogenation followed by reaction with primary amines. The direct reaction of the tetrahydrobenzofuran-4(5H)-one compounds derived from dimedone with amines gave 1-alkyl-2-alkylimino-3-aryl-6,7-dihydroindole-4(5H)-ones, while starting materials derived from 1,3-cyclohexanedione underwent an unprecedented 2-deacylation reaction and gave 1-alkyl-3-aryl-6,7-dihydroindole-4(5H)-ones.     

One-pot synthesis of 3-(furan-2-yl)-4-hydroxy-2H-chromen-2-ones using K10 montmorillonite clay as heterogeneous catalyst

A facile and efficient one-pot synthesis of 3-(furan-2-yl)-4-hydroxy-2H-chromen-2-ones was developed. The reaction of ethyl 3-(2-hydroxyphenyl)-3-oxopropanoates and 2,5-dimethoxy-2,5-dihydrofuran were performed in presence of K10 Montmorillonite Clay heterogeneous catalyst under the solvent-free condition at 80?°C for 1?h, and followed by further converted to 3-(furan-2-yl)-4-hydroxy-2H-chromen-2-ones via refluxing in the alkaline EtOH solution for 0.5?h. The demonstrate method not only avoided the usage of any expensive transition-metals, but also eliminated the tedious intermediate purification. Moreover, due to the wide functional group tolerance, it could be applied to various substrates and gave product in good to excellent yields.     

新型苯并二氢呋喃合二酮酸类化合物的合成及其与整合酶分子对接研究

以阿魏酸甲酯为原料,通过氧化偶联构建2-芳基苯并二氢呋喃骨架,再经傅克酰基化和酯缩合反应依次制得(E)-3-［2-(4-羟基-3-甲氧基-5-乙酰基)苯基-3-甲氧羰基-7-甲氧基-2,3-二氢苯［b］并呋喃-5-基］丙烯酸甲酯（3）和(E)-3-［2-(4-羟基-3-甲氧基-5-甲氧羰基乙酰基)苯基-3-甲氧羰基-7-甲氧基-2,3二氢苯并［b］呋喃-5-基］丙烯酸甲酯（4）; 4经水解反应合成3-【2-羟基-3-甲氧基-5-｛5-［2-（甲氧基羰基）乙烯基］-7-甲氧基-3-甲氧羰基-2,3-二氢苯并［b］呋喃-2-｝基】苯基-3-氧丙酸（5）,化合物3~5未见文献报道,其结构经¹H NMR, ¹³C NMR和MS(ESI)表征。采用分子对接软件Autodock vina对化合物2~5与HIV-1整合酶核心部位高度同源的PFV IN（PDB: 3L2V）进行对接,计算结果显示该类化合物能与整合酶形成稳定的复合物,具有1,3-二酮基团的化合物3, 4和5能与整合酶中金属离子产生螯合作用,其中化合物5的结合作用最强。     

New facile synthesis of furan-2(3H)-ones and 2,3,5-trisubstituted furans via intramolecular Wittig reaction of acid anhydride

A new facile preparation of furan-2(3H)-ones and 2,3,5-trisubstituted furans by a sequential O-acylation/Wittig(/O-acylation) reaction has been developed. The easily accessible 2-(triphenylphosphoranylidene)-succinic acid 1-ester 3 reacted with acid chloride produced furan-2(3H)-ones 4 in good yields in the presence of DMAP via sequential O-acylation and intramolecular Wittig reaction of acid anhydride. Subsequently, the 2,3,5-trisubstituted furans 5 were prepared from furan-2(3H)-ones 4 and diverse aryl chlorides in presence of triethylamine through further O-acylation.     

Stereoselective synthesis of β-(hydroxymethylaryl/alkyl)-α-methylene-γ-butyrolactones

Zinc or a chromium(II) source with 3-(bromomethyl)furan-2(5H)-one (3) and an aldehyde gives β-(hydroxymethylaryl/alkyl)-α-methylene-γ-butyrolactones 5 in good yields and high diastereoselectivities. The methodology is demonstrated in concise syntheses of (±)-hydroxymatairesinol (8) and (±)-methylenolactocin (10) by subsequent arylboronate conjugate addition and translactonization, respectively.     

Vitamin B12:An efficient type catalyst for the one-pot synthesis of 3,4,5-trisubstituted furan-2(5H)-ones and N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates

Vitamin B12 was applied as catalyst for the one-pot three-component synthesis of 3,4,5-trisubstituted furan-2(5H)-ones from the condensation between aldehydes, amines and dialkylacetylendicarboxylates at ambient temperature in EtOH. In addition, N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates were synthesised using mentioned catalyst at ambient temperature in EtOH from condensation between formaldehyde, amines, and dialkylacetylenedicarboxylates. This methodology has number of advantages such as:use of green and nonhazardous catalyst, clean work up, short reaction times, high yields and no need to column chromatography.     

Highly diastereoselective Friedel-Crafts reaction of furans with 8-phenylmenthyl glyoxylate

The Friedel-Crafts reaction of (1R)-8-phenylmenthyl glyoxylate with variously substituted furans was found to be efficiently promoted by SnCl(4) or magnesium salts with high diastereoselectivities. MgBr(2) performs especially well under simple, undemanding conditions, giving both high yields and high diastereoselectivities (>90%). The reaction afforded chiral substituted furan-2-yl-hydroxyacetic acid esters, compounds of potentially high synthetic interest. [reaction: see text]     

ZnO nanoparticle-catalyzed efficient one-pot three-component synthesis of 3,4,5-trisubstituted furan-2(5H)-ones

An efficient and high-yielding protocol using nano-ZnO (50–100 nm) as an efficient heterogeneous catalyst for one-pot three-component synthesis of pharmacologically significant furanone derivatives by the condensation of aromatic aldehyde, amine and dimethylacetylenedicarboxylate has been developed. Since the catalyst is heterogeneous, it can be easily separated and recycled several times without much loss of its catalytic activity. Use of aqueous medium, recyclable nanocatalyst, operational simplicity, non-chromatographic purification technique, excellent yield and short reaction time makes this approach an attractive protocol for the synthesis of 3,4,5-trisubstituted furan-2(5H)-ones.     

Substituted Butanolides and Butenolides: XVII. Substituted 3-(Furan-2-ylmethylidene)furan-2(3<Emphasis Type="Italic">H</Emphasis>)-ones and 3-(Furan-2-ylmethylidene)dihydrofuran-2(3<Emphasis Type="Italic">H</Emphasis>)-ones

A number of furan-2-ylmethylidene-substituted lactones were synthesized by condensation of 5-alkylfuran-2(3H)-ones and 4-alkyldihydrofuran-2(3H)-ones with 5-substituted furan-2-carbaldehydes. The reactivity of furan-2(3H)-ones was higher than that of furan-2(5H)-ones due to formation of intermediate conjugated anion. The condensation of 4-alkyldihydrofuran-2(3H)-ones with furan-2-carbaldehydes required more severe conditions than the condensation with furan-2(3H)-ones. The substituent in the furan ring affects the reaction time and yield.     

Synthesis of new aryl substituted furan-2(5H)-ones using the Suzuki-Miyaura reaction

A series of novel 5-arylidenefuran-2(5H)-ones and 5-arylidene-4-arylfuran-2(5H)-ones were synthesized via the Suzuki-Miyaura reactions of fimbrolide derivatives 5-(bromomethylene)furan-2(5H)-one and 4-bromo-5-(bromomethylene)furan-2(5H)-one, respectively. A regioselective Suzuki-Miyaura reaction on 4-bromo-5-(bromomethylene)furan-2(5H)-one allowed the synthesis of unsymmetrically substituted 5-arylidene-4-arylfuran-2(5H)-ones. The crystal structure of the intermediate 5-arylidene-4-bromofuran-2(5H)-one revealed interesting Br?O halogen bonding.     

Synthesis of highly fluorescent and water soluble perylene bisimide

Designed and synthesized a new highly water soluble N,N¹-bis（2-（（5-（（dimethylamino）methyl）furan-2-yl）methylthio）ethyl）-perylene -3,4,9,10-tetracarboxylic diimide from 2-（（5-（（dimethylamino）methyl）furan-2-yl）methylthio）ethanamine and perylene-3,4,9,10- tetracarboxylic dianhydride.The compound was characterized by ¹H,¹³C,2D NMR,mass and IR techniques.The compound is highly fluorescent with good solubility in water and other polar solvents.     

离子液体[2-aemim]im催化Knoevenagel反应和异噁唑酮合成

以碱性离子液体1-(2-氨基乙基)-3-甲基咪唑咪唑盐([2-aemim]im)作为催化剂,催化Knoevenagel反应和4-芳亚甲基异噁唑-5(4H)-酮衍生物的合成。实验结果表明:在无溶剂条件下,该离子液体对Knoevenagel反应具有很高的催化活性,一系列芳香醛和活泼亚甲基化合物的反应在室温条件下2 min内顺利完成,均以90%以上的高产率生成取代烯烃产物.将该碱性离子液体用于催化乙酰乙酸乙酯或苯甲酰乙酸乙酯、盐酸羟胺和芳香醛三组分一锅法缩合制备4-芳亚甲基异噁唑-5(4H)-酮衍生物,具有反应时间较短、产率较高和后处理简单的特点。离子液体经简单处理后能多次循环使用。     

Synthesis of C1-symmetric chiral secondary diamines and their applications in the asymmetric copper(II)-catalyzed Henry (nitroaldol) reactions

A small library of C(1)-symmetric chiral diamines (L1-L9) was constructed via condensing exo-(-)-bornylamine or (+)-(1S,2S,5R)-menthylamine with various Cbz-protected amino acids. Among them, ligand L1/CuCl(2)·2H(2)O complex (2.5 mol %) shows outstanding catalytic efficiency for Henry reaction between a variety of aldehydes and nitroalkanes to afford the expected products in high yields (up to 98%) with excellent enantioselectivities (up to 99%) and moderate to good diastereoselectivities (up to 90:10). This process is air- and moisture tolerant and has been applied to the synthesis of (S)-2-amino-1-(3,4-dimethoxyphenyl)ethanol (9), a key intermediate for (S)-epinephrine and (S)-norepinephrine. On the basis of HRMS and X-ray diffraction analysis of the L1/CuCl(2) complex, a transition-state model was proposed to explain the origin of asymmetric induction. The low catalyst loading, excellent yields and enantioselectivities, inexpensive copper salt, and mild reaction conditions make our catalytic system to be practically useful.     

Chiral squaramide-catalyzed highly diastereo- and enantioselective direct Michael addition of nitroalkanes to nitroalkenes

An efficient highly diastereo- and enantioselective direct Michael addition of nitroalkanes to nitroalkenes catalyzed by chiral squaramide catalyst has been developed. This organocatalytic reaction with a low catalyst loading (2 mol%) proceeded well to afford synthetically useful 1,3-dinitro compounds in high yields with high diastereoselectivities (up to 95 : 5 dr) and excellent enantioselectivities (up to 97% ee).     

Synthesis of spirocyclic azacycles from the cyclization of furan tethered N-acyliminium ions

The protic and Lewis acid promoted cyclization reactions of tethered furan-4,5-dihydroxypiperid-2-ones, furan-4,5-diacetoxypiperid-2-ones and furan-3,4-diacetoxypyrrolid-2-ones, via their corresponding N-acyliminium ion intermediates, have been studied. In the case of the furan-4,5-dihydroxypiperid-2-one 2a and its diacetate derivative 2b, macrocyclic products were formed from an initial intermolecular reaction between 2a or 2b, via the nucleophilic C5 furan carbon, and their corresponding N-acyliminium ion intermediates. When the furan C5 position of 2b was blocked by substitution with bromine then TFA or Sc(OTf)₃ catalysed cyclization reactions gave a spirotricyclic product (a 5-6-6-tricycle) in a highly diastereoselective manner. Cyclization of the analogous C5-Br-furan-pyrrolidone 29 with TFA resulted in a related spirotricyclic (a 5-6-5 tricycle) product. Attempts to prepare an analogous azepine system, a 5-7-5 tricycle, were not successful. Cyclization reactions of the C5-PhS-furan- or C5-phenylsulfonyl-pyrrolidone analogues of 29 with TFA were also not successful.     

Synthesis of pyridone-substituted furan-2(5H)-ones and their intramolecular cyclization to afford furo[3,4-f]isoquinolines

Chemistry of Heterocyclic Compounds - Synthetic approach toward pyridone-substituted furan-2(5H)-ones has been described. Intramolecular cyclization of these compounds leads to novel 7-substituted...     

Reformatsky reaction of methyl 1-bromocycloalkane-1-carboxylates with phenyl-and benzoylhydrazones derived from aromatic aldehydes

Reformatsky reagents obtained from methyl 1-bromocyclohexane-and 1-bromocyclopentane-1-carboxylates reacted with aromatic aldehyde phenyl-and benzoylhydrazones to give 3-aryl-2-phenylamino-2-azaspiro[3.5]nonan-, 3-aryl-2-phenylamino-2-azaspiro[3.4]octan-, 3-aryl-2-benzoylamino-2-azaspiro[3.5]-nonan-, and 3-aryl-2-benzoylamino-2-azaspiro[3.4]octan-1-ones, respectively. The reaction of furan-2-carbaldehyde phenylhydrazone with methyl 1-bromocyclohexane-1-carboxylate and zinc led to the formation of 4-(2-furyl)-2-phenyl-2,3-diazaspiro[4.5]decan-1-one.