摘要:
An unprecedented I2/FeCl3-promoted cascade reaction of aryl methyl ketones with 8-aminoquinolines for the convenient synthesis of (E)-3-(2-acyl-1H-benzo[d]imidazol-4-yl)acrylaldehydes was developed by merging annulation with ring deconstruction. This novel strategy unlocked the new reactivity of 8-aminoquinolines and provided an attractive platform for the ring opening of unactivated N-heteroaromatic compounds. Preliminary mechanistic investigation suggested that dual C(sp3)–H amination/C–N bond cleavage were key reaction steps. Furthermore, late-stage modification of the obtained products successfully delivered pyrazole and isoxazole derivatives, increasing the practicability and application potential of this methodology in organic synthesis.
通讯机构:
[Wu, An-Xin] C;[Yin, Guodong] H;Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Peoples R China.;Hubei Normal Univ, Coll Chem & Chem Engn, Hubei Key Lab Pollutant Anal & Reuse Technol, Huangshi 435002, Hubei, Peoples R China.
摘要:
A novel and efficient multicomponent cyclization of methyl ketones, cyanamides, and arylamines for the synthesizing 2,4-diamino-1,3,5-triazines via consecutive formation of four C–N bonds is reported. This multicomponent reaction is characterized by the employment of two molecules of cyanamide for double C(sp3)–H amination of methyl ketones, avoiding complicated prepreparation of substrates and expanding the substrate scope. Furthermore, this multicomponent cyclization strategy provides a new approach for generating diverse 2,4-diamino-1,3,5-triazines with a broad substrate scope under mild conditions.
通讯机构:
[Wu, An-Xin] C;[Zhu, Yan-Ping] Y;Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Peoples R China.;Yantai Univ, Sch Pharm, Key Lab Mol Pharmacol & Drug Evaluat, Minist Educ,Collaborat Innovat Ctr Adv Drug Deliv, Yantai 264005, Shandong, Peoples R China.
摘要:
The first synthesis of arylquinazolinones has been disclosed via the consecutive oxidative cyclization/ring-opening of anilines and methyl ketones. This transformation is characterized by the splitting of the methyl ketone as acyl and C1 sources through C(CO)–C(sp3) bond cleavage, using DMSO as a C1 source via C–S bond cleavage, which expands the use of methyl ketones as valuable building blocks and enriches the library of preparation quinazolinones. Moreover, preliminary mechanistic studies indicate that this multicomponent reaction underwent a consecutive cyclization/ring-opening sequence.
通讯机构:
[Wu, An-Xin] C;[Zhao, Zhi-Yong] W;Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Peoples R China.;Wuhan Univ Sci & Technol, State Key Lab Refractories & Met, Sch Chem & Chem Engn, Wuhan 430081, Peoples R China.
摘要:
A novel method for the synthesis of 5H-benzo[a]fluoren-5-one from inactive nonterminal 1,6-alkynes through a free radical tandem bicyclization process has been established. This process achieved a continuous cyclization triggered rarely by the α-position of α,β-unsaturated ketones. The reaction constructed three C–C bonds in one step with the readily accessible substrates and excellent substrate compatibility.
作者机构:
[Liu, Yi; Cai, Qun; Yang, Mian; Peng, Na] Wuhan Univ Sci & Technol, Sch Chem & Chem Engn, Coal Convers & New Carbon Mat Key Lab Hubei Prov, Wuhan 430081, Hubei, Peoples R China.;[Zhuang, Shiyi; Wu, Anxin] Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Hubei, Peoples R China.;[Liu, Yi] Wuhan Univ, Coll Chem & Mol Sci, State Key Lab Virol, Wuhan 430072, Hubei, Peoples R China.;[Liu, Yi] Wuhan Univ, Coll Chem & Mol Sci, Key Lab Analyt Chem Biol & Med MOE, Wuhan 430072, Hubei, Peoples R China.
通讯机构:
[Wu, Anxin] C;Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Hubei, Peoples R China.
关键词:
Tandem cyclization;I-2 promoted;Aryl methyl ketones;4-Hydroxycoumarins;Pyrano[3,2-c]chromene-2,5-diones
摘要:
An efficient and convenient method for the synthesis of various substituted pyrano[3,2-c]chromene-2,5-diones was developed via the I-2-promoted tandem cyclization of commercially available aryl methyl ketones and 4-hydroxycoumarins. Preliminary mechanism studies indicated that the reaction involved a consecutive iodination/Kornblum oxidation/annulation process. HI produced in the I-2-DMSO system acted as an important promoter, accelerating the annulation protocol. (C) 2019 Elsevier Ltd. All rights reserved.
通讯机构:
[Shu, Wen-Ming] Y;[Wu, An-Xin] C;Yangtze Univ, Coll Chem & Environm Engn, Jingzhou 434023, Peoples R China.;Cent China Normal Univ, Minist Educ, Coll Chem, Key Lab Pesticide & Chem Biol, Wuhan 430079, Hubei, Peoples R China.
摘要:
A molecular iodine-mediated coupling cyclization reaction for the synthesis of 4-aryl-NH-1,2,3-triazoles has been developed from N-tosylhydrazones and sodium azide. This metal-free cascade [4 + 1] cyclization reaction could rapidly synthesize valuable compounds via a sequential C-N and N-N bond formation. Mechanistic studies demostrate that the nitrogen atoms of the 1,2,3-triazoles are not entirely from sodium azide.
摘要:
An acid-mediated multicomponent reaction has been developed for the direct synthesis of multifused 1,3-benzoxazine derivatives from simple and readily available arylglyoxal monohydrates and 2-aminobenzyl alcohols under mild conditions. This novel protocol is proposed to proceed through intramolecular poly-heterocyclizations, thus leading to the formation of three new rings and six new chemical bonds, including four CN and two CO bonds.
通讯机构:
[Wu, YD; Wu, AX] C;Cent China Normal Univ, Coll Chem, Minist Educ, Key Lab Pesticide & Chem Biol, Wuhan 430079, Hubei, Peoples R China.
摘要:
A novel and efficient formal [4 + 2+1] annulation of aryl methyl ketones and 2-aminobenzyl alcohols for the synthesis of benzo[e][1,4]diazepin-3-ones is reported. This reaction successfully affords diverse seven-membered ring lactams via dual C–O bond cleavage. A preliminary mechanistic study showed that a multicomponent dicyclization and ring-opening sequence might occur, with the introduction of methyl sulfide proposed as the last step. This efficient strategy with mild reaction conditions and a broad substrate scope has potential applications in chemistry and medicine.
通讯机构:
[Shu, Wen-Ming] Y;[Wu, An-Xin] C;Yangtze Univ, Coll Chem & Environm Engn, Jingzhou 434023, Peoples R China.;Cent China Normal Univ, Minist Educ, Key Lab Pesticide & Chem Biol, Coll Chem, Wuhan 430079, Hubei, Peoples R China.
摘要:
A novel DMSO-involved cascade reaction of stabilized sulfonium salts has been established for direct construction of polyfunctional furans. This one-pot sequential reaction involving in situ generated alpha-methylene sulfonium salts was followed by [4 + 1] annulation with sulfur ylides. Notably, DMSO plays a very important role in this transformation, not only as a solvent but also as one carbon source.
摘要:
A new strategy has been developed for the synthesis of 2,5-disubstituted oxazoles from easily available arylacetylenes and α-amino acids in the presence of Cu(NO<sub>3</sub>)<sub>2</sub>•3H<sub>2</sub>O and iodine. This reaction process involves the I<sub>2</sub>/Cu(NO<sub>3</sub>)<sub>2</sub>•3H<sub>2</sub>O-assisted transformation of arylacetylene to α-iodo acetophenone, Kornblum oxidation to phenylglyoxal, condensation to imine, decarboxylation/annulation/oxidation reaction sequence to approach 2,5-disubstituted oxazoles.
通讯机构:
[Wu, An-Xin] C;[Wang, Jun-Gang] G;Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Hubei, Peoples R China.;Guizhou Minzu Univ, Sch Chem Engn, Guiyang 550025, Guizhou, Peoples R China.
摘要:
An efficient I2-DMSO reagent system-mediated multicomponent reaction strategy for the synthesis of C3-sulfenylated chromones from o-hydroxyaryl methyl ketones, rongalite, and dimethyl sulfoxide has been developed. Notably, the double C-S bond cleavages of rongalite and dimethyl sulfoxide served as key steps in this smooth transformation, affording the C1 unit and sulfur source for the assembly of C3-sulfenylated chromones. Preliminary mechanistic studies indicated that in situ generated HCHO and (2-(2-hydroxyphenyl)-2-oxoethyl)dimethylsulfonium iodine were probably the key intermediates in this transformation.
通讯机构:
[Zhu, Yan-Ping] Y;[Wu, An-Xin] C;Yantai Univ, Key Lab Mol Pharmacol & Drug Evaluat, Collaborat Innovat Ctr Adv Drug Delivery Syst & B, Sch Pharm,Minist Educ, Yantai 264005, Shandong, Peoples R China.;Cent China Normal Univ, Key Lab Pesticide & Chem Biol, Minist Educ, Coll Chem, Wuhan 430079, Hubei, Peoples R China.
摘要:
We herein describe an oxidative [4 + 1] annulation used to prepare 1,2,4-triazolo[4,3-a] pyridines in the presence of I-2-DMSO. This protocol enables synthesis of triazolo[4,3-a] pyridine-quinoline linked diheterocycles via a direct oxidative functionalization of sp(3) C-H bonds of 2-methyl-azaheteroarenes. The reaction shows a wide substrate scope and good functional group tolerance.
作者机构:
[Huang, Chun; Feng, Ling-ling; Feng, AX; Wang, Can; Feng, An-Xin; Zhou, You; Geng, Xiao; Bao, Yang; Zhao, Peng] Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Peoples R China.;[Feng, An-Xin] Lanzhou Univ, State Key Lab Appl Organ Chem, Lanzhou 730000, Peoples R China.
通讯机构:
[Feng, LL; Feng, AX] C;[Feng, An-Xin] L;Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Peoples R China.;Lanzhou Univ, State Key Lab Appl Organ Chem, Lanzhou 730000, Peoples R China.
摘要:
We report an I2/FeCl3-co-promoted formal [2 + 2+1] annulation of aryl methyl ketones, 2-aminobenzyl alcohols, and p-toluenesulfonylmethyl isocyanide (TosMIC) by neighboring group (-CH2OH) assistance. This is a novel example of using the Van Leusen reagent as a unique C1N1 "two-atom synthon" in the synthesis of imidazoles. Preliminary mechanism studies showed that TsCH2NH2 might be the key intermediate in this reaction. Furthermore, this reaction not only unlocks a novel strategy for imidazole synthesis, but also exploits a new reactivity of TosMIC.