- Visible Light-Promoted Magnesium, Iron, and Nickel Catalysis Enabling C(sp3)-H Lactonization of 2-Alkylbenzoic Acids
-
A mild and practical C(sp3)-H lactonization protocol has been achieved by merging photocatalysis and magnesium (iron, nickel) catalysis. A diverse range of 2-alkylbenzoic acids with a variety of substitution patterns could be transformed into the corresponding phthalide products. Based on the mechanistic experimentation and reported prior studies, a possible mechanism for the benzylic oxidative lactonization reaction was proposed with the hypothetic photoactive ternary complex formed between the 2-alkylbenzoic acid substrate, magnesium ion, and bromate anion.
- Li, Sasa,Su, Mincong,Sun, Jie,Hu, Kunjun,Jin, Jian
-
supporting information
p. 5842 - 5847
(2021/07/31)
-
- Synthesis of 1,2-phenylenedimethanols by base-promoted reduction of isobenzofuran-1(3H)-ones with silane
-
An efficient method for preparation of substituted 1,2-phenylenedimethanols and aliphatic 1,4-diols that are valuable intermediates in organic synthesis, has been developed by the base-promoted reduction of isobenzofuran-1(3H)-ones and γ-lactones with silane under mild conditions. Compared with traditional procedures using stoichiometric amounts of metal hydrides and alkyl reductants, the present method avoids the use of sensitive reagents and is operationally simple and a broad variety of functional groups are tolerated.
- Liu, Bin,Zhou, Xigeng
-
supporting information
p. 725 - 728
(2018/12/11)
-
- Saturated oxygen and nitrogen heterocycles: Via oxidative coupling of alkyltrifluoroborates with alkenols, alkenoic acids and protected alkenylamines
-
Saturated heterocycles are important components of many bioactive compounds. The method disclosed herein enables a general route to a range of 5-, 6- and 7-membered oxygen and nitrogen heterocycles by coupling potassium alkyltrifluoroborates with heteroat
- Shikora, Jonathan M.,Um, Chanchamnan,Khoder, Zainab M.,Chemler, Sherry R.
-
p. 9265 - 9269
(2019/10/22)
-
- Palladium-Catalyzed Direct Oxidative Coupling of Iodoarenes with Primary Alcohols Leading to Ketones: Application to the Synthesis of Benzofuranones and Indenones
-
In the present study, a palladium-catalyzed direct oxidative acylation through cross-dehydrogenative coupling has been investigated, utilizing readily available primary alcohols as acylating sources. Overall, this oxidative coupling proceeds via three distinct transformations such as oxidation, radical formation, and cross-coupling in one catalytic process. This protocol does not involve the assistance of a directing group or activation of the carbonyl group by any other means. Furthermore, this reaction made use of no toxic CO gas as carbonylating agent; instead, feedstock primary alcohols have been utilized as acylation source. Notably, the synthesis of benzofuranones and indenones is enabled. This strategy was also applied to the synthesis of n-butylphthalide, fenofibrate, pitofenone, and neo-lignan.
- Suchand, Basuli,Sreenivasulu, Chinnabattigalla,Satyanarayana, Gedu
-
p. 4832 - 4843
(2019/07/31)
-
- Electron-Transfer-Induced Intramolecular Heck Carbonylation Reactions Leading to Benzolactones and Benzolactams
-
A metal-catalyst-free intramolecular Heck carbonylation reaction of benzyl alcohols and benzyl amines with carbon monoxide under heating at 250 °C affords the corresponding benzolactones and benzolactams in good to excellent yields. A hybrid radical/ionic chain mechanism, involving electron transfer from radical anions generated by nucleophilic attack of alcohols or amines on intermediate acyl radicals, is proposed.
- Fukuyama, Takahide,Bando, Takanobu,Ryu, Ilhyong
-
supporting information
p. 3015 - 3021
(2018/06/08)
-
- Ruthenium-Catalyzed Enantioselective Hydrogenation/Lactonization of 2-Acylarylcarboxylates: Direct Access to Chiral 3-Substituted Phthalides
-
Highly enantioselective tandem hydrogenation/lactonization of various 2-acylarylcarboxylates including 2-aroylarylcarboxylates were realized by using [RuCl(benzene)(S)-SunPhos]Cl as the catalyst under mild reaction conditions. Excellent enantioselectivities (up to 99.6 % ee) and activities (S/C=1000) were obtained. This convenient and practical method enables a direct access to a series of highly optically pure 3-substituted phthalides that are very important molecules as valuable pharmacological compounds and diversified synthons for medicinal chemistry. Moreover, a gram-scale reaction was performed to further demonstrate the practicality of this approach.
- Lu, Bin,Zhao, Mengmeng,Ding, Guangni,Xie, Xiaomin,Jiang, Lili,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
-
p. 3989 - 3996
(2017/09/13)
-
- Domino [Pd]-Catalysis: One-Pot Synthesis of Isobenzofuran-1(3H)-ones
-
An efficient domino [Pd]-catalysis for the synthesis of isobenzofuran-1(3H)-ones is presented. The strategy shows broad substrate scope and is amenable to o-bromobenzyl tertiary/secondary/primary alcohols. Significantly, the method was applied to the synthesis of antiplatelet drug n-butyl phthalide and cytotoxic agonist 3a-[4′-methoxylbenzyl]-5,7-dimethoxyphthalide.
- Mahendar, Lodi,Satyanarayana, Gedu
-
p. 7685 - 7691
(2016/09/09)
-
- Cu-MEDIATED ANNULATION FOR THE EFFECTIVE SYNTHESIS OF 3-SUBSTITUTED PHTHALIDES
-
The present invention disclosed herein is a novel commercially feasible, one pot synthesis of library of 3-substituted phthalides of formula I via CuCN mediated oxidative cyclization in high yield. Formula I
- -
-
Page/Page column 0072; 0116; 0117
(2015/02/25)
-
- Cu-MEDIATED ANNULATION FOR THE EFFECTIVE SYNTHESIS OF 3-SUBSTITUTED PHTHALIDES
-
The present invention disclosed herein is a novel commercially feasible, one pot synthesis of library of 3-substituted phthalides of formula I via CuCN mediated oxidative cyclization in high yield. Formula I
- -
-
Page/Page column 20
(2013/07/19)
-
- Synthesis, resolution, and antiplatelet activity of 3-substituted 1(3H)-isobenzofuranone
-
A series of 3-substituted-1(3H)-isobenzofuranone 6a-g and 7a-g were synthesized from phthalic anhydride. The compound 6a-g was resolved. The antiplatelet activities of these compounds were evaluated using in vitro experiment of platelet aggregation. The levels of antiplatelet activity were displayed as following sequence: l-isomer > dl-isomer > d-isomer, respectively. The alkylphthalide is more active than the corresponding alkenephthalide. All these compounds were less active than n-butylphthalide (NBP, 6c) and Aspirin (Asp).
- Yang, Hua,Hu, Gao-Yun,Chen, Jun,Wang, Yi,Wang, Zhong-Hua
-
p. 5210 - 5213
(2008/02/11)
-
- Highly efficient cyclization of o-iodobenzoates with aldehydes catalyzed by cobalt bidentate phosphine complexes: A novel entry to chiral phthalides
-
Methyl 2-iodobenzoates 1a-c undergo cyclization reactions with various aromatic aldehydes 2a-m (RC6CHO: R = H 2a, 4-CH3, 2b, 4tBu 2c, 4-OMe 2d, 3-OMe 2e, 4-C1 2f, 4-CF3 2g, 4-CN 2h, 4-Ph 2i; benzo [d][1,3]dioxole-5-carbaldehyde (2j), 1napthaldehyde (2k), benzofuran-2- carbaldehyde (21), and isonicotinaldehyde (2m)) in the presence of [CoI2(dppe)] (dppe = l,2-bis(diphenylphosphino)ethane) and Zn powder in dry THF at 75 °C for 24 h to give the corresponding phthalide derivatives 3a-m and 3q-t in good to excellent yields. Under similar reaction conditions, less reactive aliphatic aldehydes, heptanal (2n), butyraldehyde (2o), and 2-phenylacetaldehyde (2p) also underwent cyclization reactions with la to provide 3n-p, respectively, in fair to good yields. The catalytic reaction can be further extended to cinnamyl aldehyde (2q) with la to give the corresponding phthalide derivative 3u. This synthetic method is compatible with a variety of functional groups on the aryl ring of 2. The high efficiency of the cobalt catalyst containing a dppe (dppe = l,2-bis(diphenylphosphino)ethane) ligand encouraged us to investigate the asymmetric version of the present catalytic reaction by employing bidentate chiral ligands. Thus, aromatic aldehydes 2a-c, 2f, and 2 g undergo cyclization with 2-iodobenzoate (la) smoothly in the presence of [CoI2{(S,S)- dipamp}] ((S,S)-dipamp = (1S,2S)-(+)-bis[2-methoxyphenyl]phenylphosphino)ethane) and zinc powder in THF at 75 °C for 24 h, giving the corresponding (S)-phthalides 4a-e in 8189 % yields with 70-98 % ee. A possible mechanism for the present catalytic reaction is proposed.
- Chang, Hong-Tai,Jeganmohan, Masilamani,Cheng, Chien-Hong
-
p. 4356 - 4363
(2008/02/05)
-
- Efficient synthesis of isobenzofuran-1(3H)-ones (Phthalides) and selected biological evaluations
-
The studies presented here deal with the convenient and efficient one-step conversion of o-alkylbenzoic acids into their corresponding isobenzofuran-1 (3H)-ones (phthalides) using NaBrO3/NaHSO3 in a two-phase system. A range of o-alkylbenzoic acids was used with the object of getting a variety of phthalide derivatives as multipurpose biologically active compounds. Seventeen phthalides have been synthesized and tested for cytotoxicity, antibacterial and antifungal activities. Some of these compounds showed promising cytotoxic effects against Artemia salina. Compounds 4j-4p were highly active against Gram-negative and Gram-positive bacteria among all tested compounds. In the fungicidal assay, the compounds showed a broad spectrum of activity against six fungi. All compounds were characterized via elemental analysis, UV, IR, mass and-NMR spectroscopy. ECV · Editio Cantor Verlag.
- Bayer, Ernst,Hayat, Safdar,Atta-Ur-Rahman,Choudhary, M. Iqbal,Khan, Khalid Mohammed,Shah, Syed Tasadaque Ali,Imran-Ul-Haq,Anwar, M. Usman,Voelter, Wolfgang
-
p. 588 - 597
(2007/10/03)
-
- Synthesis of phthalide derivatives using nickel-catalyzed cyclization of o-haloesters with aldehydes
-
The reaction of o-bromobenzoate (1b) with benzaldehyde (2a) in the presence of [NiBr2(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane) and zinc powder in THF (24 hours, reflux temperature), afforded 3-phenyl-3H- isobenzofuran-1-one (3a) in an 86% yield. Similarly, o-iodobenzoate reacts with 2a to give 3a, but in a lower yield (50%). A series of substituted aromatic and aliphatic aldehydes (2b, 4-MeC6H4CHO; 2c, 4-MeOC 6H4CHO; 2d, 3-MeOC6H4-CHO 2e, 2-MeOC6H4-CHO; 2f, 4-CNC6H4CHO; 2g, 4-(Me)3-CC6H4CHO; 2h, 4-C6H 4C6H4CHO; 2i, 4-ClC6H 4CHO; 2j, 4-CF3C6H4CHO; 2k, CH 3(CH2)5CHO; 21, CH3(CH 2)2-CHO) also underwent cyclization with o-bromobenzoate (1b) producing the corresponding phthalide derivatives in moderate to excellent yields and with high chemoselectivity. Like 1b, methyl 2-bromo-4,5- dimethoxybenzoate (1c) reacts with tolualdehyde (2b) to give the corresponding substituted phthalide 3m in a 71% yield. The methodology can be further applied to the synthesis of six-membered lactones. The reaction of methyl 2-(2-bromophenyl)acetate (1d) with benzaldehyde under similar reaction conditions afforded six-membered lactone 3o in a 68% yield. A possible catalytic mechanism for this cyclization is also proposed.
- Rayabarapu, Dinesh Kumar,Chang, Hong-Tai,Cheng, Chien-Hong
-
p. 2991 - 2996
(2007/10/03)
-
- An alternative method for the synthesis of γ-lactones by using cesium fluoride-celite/acetonitrile combination
-
A variety of 2-(1-bromoalkyl) benzoic acids 4 undergo intramolecular nucleophilic substitution reaction when treated with a CsF-Celite as solid base in acetonitrile under reflux condition to give the corresponding cyclized phthalides in moderate to very good yield. These 2-(1-bromoalkyl) benzoic acids 4 are formed by the α-bromination of 2-alkylbenzoic acids 3 using N-bromosuccinimide and a catalytic amount of α,α′ -azoisobutyronitrile in carbon tetrachloride under reflux.
- Khan, Khalid Mohammed,Hayat, Safdar,Zia-Ullah,Atta-ur-Rahman,Iqbal-Choudhary,Maharvi, Ghulam Murtaza,Bayert, Ernst
-
p. 3435 - 3453
(2007/10/03)
-
- An improved method for the synthesis of γ-lactones using sodium bromate and sodium hydrogen sulfite
-
o-Alkylbenzenecarboxylic acids are treated with a sodium bromate and sodium hydrogen sulfite reagent under a two-phase system using ethyl acetate as solvent, under mild conditions to give the corresponding cyclized phthalides in moderate to satisfactory yield. Intermediately the α-brominated alkylbenzenecarboxylic acids are formed by the in situ generated hypobromous acid. These α-brominated acids undergo an intramolecular nucleophilic substitution reaction to afford the corresponding γ-lactones.
- Hayat, Safdar,Atta-ur-Rahman,Choudhary, M. Iqbal,Khan, Khalid Mohammed,Bayer, Ernst
-
p. 1647 - 1649
(2007/10/03)
-
- Functional-Group-Directed Diastereoselective Hydrogenation of Aromatic Compounds. 21
-
Diastereoselective liquid-phase hydrogenation of a series of monosubstituted indan substrates was studied on supported rhodium catalysts. Predominantly the cis-cis diastereomer, obtained by hydrogenation from the diastereoface opposite the substituent at the stereogenic center, and the cis-trans diastereomer, obtained by hydrogenation from the diastereoface on the same side as the substituent, were formed. The diastereoselectivity depends on the balance between steric repulsion and electronic attraction of the substituent with the surface of the catalyst. For alkoxy and carboxyl groups (acid, methyl ester, and amide), the steric repulsion dominated and the cis-cis diastereomer was obtained with moderately high selectivity. The diastereoselectivity obtained in the hydrogenation was influenced by the addition of bases to the reaction mixture. Addition of triethylamine caused a small increase in the selectivity to the cis-cis diastereomer in some substrates, whereas the addition of NaOH significantly increased the selectivity toward the cis-trans isomer in all substrates.
- Ranade, Vidyadhar S.,Consiglio, Giambattista,Prins, Roel
-
p. 1132 - 1138
(2007/10/03)
-