Tandem Cooperative Friedel-Crafts Reaction of Aldehydes with Electron Deficient Arenes Through Catalyst-Activation via Hydrogen Bonding Network DOI Creative Commons
Sanjay Kumar Singh, Sankalan Mondal, Vikas Tiwari

и другие.

Опубликована: Июль 20, 2022

Since its discovery in 1877, the Friedel-Crafts alkylation reaction has been method of choice to prepare various aryl hydrocarbons. Recent developments for this have resulted synthesis these compounds one pot process with metal as well free protocols. However, common feedstock aldehydes using electron-deficient arenes and also two different arene nucleophiles are quite challenging scantily explored. Herein, we provide a solution problems by new concept, “catalyst activation” accomplished increasing Brønsted acidity p-toluenesulfonic acid (pTSA) through strong hydrogen bonding hexafluoroisopropanol (HFIP). The real-time NMR titration, computational studies, reveal multiple roles HFIP para-toluene sulphonic stabilization transition states formed during electrophilic aromatic substitution. developed great potential industrial application reflected bio-active natural products like arundine, tartarinoid C, several other bioactive molecules. Also, used was recovered gram-scale making protocol highly cost-effective conducive production.

Язык: Английский

Pnictogen‐Bonding Catalysts, Compared to Tetrel‐Bonding Catalysts: More Than Just Weak Lewis Acids DOI Creative Commons
Hao Chen, Antonio Frontera, M. Ángeles Gutiérrez López

и другие.

Helvetica Chimica Acta, Год журнала: 2022, Номер 105(12)

Опубликована: Окт. 25, 2022

Abstract A hyperresponsive tool to assess supramolecular catalysis, the cyclization of di‐epoxides into cyclic ethers is used elucidate difference between pnictogen‐bonding and Lewis acid catalysis systematically. For all stereoisomers, most tested catalysts follow Baldwin rules. Brønsted anion–π afford almost only products. acids such as SbCl 3 , BF BiCl give poorest selectivity, with at least 50 % (B) products for stereoisomers. In clear contrast, optimized operating on Sb(III) Sb(V) level fused anti‐ (A) bicycles main product trans epoxides, independent syn or anti relation two epoxides. cis series, BA exclusively diastereomers, while diastereomers equal amounts AB show similarly special trends. These unique characteristics support that differs from can arguably be defined its non‐covalent counterpart, just like hydrogen‐bonding understood appreciated counterpart catalysis. Computational studies origin selectivity reveal an introvert deep σ hole surrounded by planar ring ligands. Central pnictogen‐bond attraction against peripheral steric repulsion then forces epoxide break open. transient antimony oxidation in intermediates accounts chemoselectivity catalysts. Presumably due insufficient accessibility their holes, activity tetrel‐bonding negligible. The division powerful irrelevant does not exist respective orthodox thus supports σ‐hole are same.

Язык: Английский

Процитировано

21
Bioinspired Synthesis of Spirochensilide A from Lanosterol DOI
Xianwen Long, Jun Li, Feng Gao

и другие.

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(36), С. 16292 - 16297

Опубликована: Сен. 2, 2022

A bioinspired synthesis of spirochensilide from commercially available lanosterol is reported. The features a directed C–H oxidation, Wagner–Meerwein-type double methyl migration, Meinwald rearrangement, and double-bond isomerization/spiroketal formation cascade. proposed biosynthetic speculation was modified by this synthetic sequence, which also served as platform for the other lanostanes with migrating groups.

Язык: Английский

Процитировано

19
Stereospecific Dehydroxytrifluoromethylthiolation of Alcohols Promoted by a Combination of Hypervalent Trifluoromethylthio-iodine(III) Reagent and N-Heterocyclic Carbene DOI
Xiaoguang Yang, Junjie Li,

Feng‐Huan Du

и другие.

Organic Letters, Год журнала: 2023, Номер 25(17), С. 2964 - 2969

Опубликована: Апрель 20, 2023

Direct dehydroxytrifluoromethylthiolation of alcohols is an attractive strategy for accessing CF3S-containing compounds. Herein, we report a method by using the combination hypervalent iodine(III) reagent TFTI and N-heterocyclic carbenes. This shows excellent stereospecificity chemoselectivity to give product with clean inversion configuration hydroxyl groups as well can be used late-stage modification structurally complex alcohols. The reaction mechanism proposed experimental computational evidence.

Язык: Английский

Процитировано

11
Direct trifluoromethylthiolation of terminal alkynes mediated by a hypervalent trifluoromethylthio-iodine(iii) reagent; boosting effect of fluorinated alcohol DOI

Yu-Xin Cheng,

Xiaoguang Yang,

Feng‐Huan Du

и другие.

Green Chemistry, Год журнала: 2024, Номер 26(10), С. 5914 - 5920

Опубликована: Янв. 1, 2024

We reported a direct simple trifluoromethylthiolation reaction of various terminal alkynes using new hypervalent trifluoromethylthio-iodine( iii ) reagent TFTI in fluorinated alcohol, either hexafluoro-2-propanol or perfluoro- tert -butanol.

Язык: Английский

Процитировано

4
Total synthesis of breviscapin B via intramolecular dehydrative etherification DOI
Kosho Makino,

Chiharu Nogami,

Shunsuke Sueki

и другие.

Organic & Biomolecular Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

The total synthesis of breviscapin B, a norlignan natural product having an unusual 2,2-diaryltetrahydrofuran skeleton, has been achieved via intramolecular dehydrative Williamson ether as key step.

Язык: Английский

Процитировано

0
Biomimetic chlorine-induced polyene cyclizations harnessing hypervalent chloroiodane–HFIP assemblies DOI Creative Commons
Julia Katharina Binder, Aniruddha Biswas, Tanja Gulder

и другие.

Chemical Science, Год журнала: 2023, Номер 14(14), С. 3907 - 3912

Опубликована: Янв. 1, 2023

A selective and generally applicable concept of the yet scantly investigated chlorination-induced polyene cyclization utilizing HFIP–chloroiodane networks mimicking terpene cyclase has been developed.

Язык: Английский

Процитировано

10
Studies on the Biomimetic Synthesis of Marine Ladder Polyethers via Endo‐Selective Epoxide‐to‐Epoxonium Ring‐Opening Cascades DOI
Jiaxi Xiao,

Feng‐Xing Li,

Shu‐Jian Ren

и другие.

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(30)

Опубликована: Май 16, 2024

Abstract Marine ladder polyethers have attracted the attention of chemists and biologists because their potent biological activities. Synthetic attempted to construct polyether frameworks by epoxide ring‐opening cascades, as Nakanishi hypothesis describes. However, Baldwin's rules ring closure state that exo ‐selective intramolecular cyclization epoxy alcohols is preferred over endo cyclization. Herein, we investigated cascades polyepoxy in [EMIM]BF 4 /PFTB (1‐ethyl‐3‐methylimidazolium tetrafluoroborate /perfluoro‐ tert ‐butyl alcohol) found all‐ products were formed via epoxide‐to‐epoxonium cyclizations (not restricted rules, which only apply hydroxyl‐to‐epoxide cyclizations). We determined key factor enabling undergo a high proportion was inhibition starting from terminal hydroxyl group alcohol. By introducing slow‐release protecting group, could markedly increase yields fragments with hydrogen atoms at junctions. For first time, constructed consecutively fused six‐membered‐ring seven‐, eight‐, nine‐membered‐ring through addition suitable Lewis acid. also suggest biosynthesis marine may proceed polyepoxide.

Язык: Английский

Процитировано

2
Synthesis and Properties of Thieno[2′,3′,4′:4,5]naphtho[1,8-cd]pyridines DOI

Ricardo Molenda,

Jonas Polkaehn,

Miguel Andre Argüello Cordero

и другие.

The Journal of Organic Chemistry, Год журнала: 2023, Номер 88(13), С. 8802 - 8824

Опубликована: Июнь 6, 2023

Thieno[2',3',4':4,5]naphtho[1,8-cd]pyridines, S,N-doped pyrene analogs, were prepared by combination of Pd catalyzed cross-coupling reactions and acid-mediated cycloisomerization. The modular scope the synthesis allowed for access to a variety functionalized derivatives. photophysical properties have been studied in detail steady-state femtosecond transient absorption accompanied cyclic voltammetry (TD)-DFT calculations. introduction five-membered thiophene into 2-azapyrene scaffold leads redshifted emission substantial effects on excited state dynamics, e.g., quantum yield, lifetime, decay rates, ISC ability, which can be further tuned substitution pattern heterocyclic scaffold.

Язык: Английский

Процитировано

5
Synthesis and reactivity of N-heterocyclic carbene (NHC) gold-fluoroalkoxide complexes DOI Creative Commons

Pierre Arnaut,

Nestor Bracho Pozsoni, Fady Nahra

и другие.

Dalton Transactions, Год журнала: 2024, Номер 53(28), С. 11952 - 11958

Опубликована: Янв. 1, 2024

We report a new family of gold-fluoroalkoxide complexes bearing various NHC ligands, and gauge their potential in organometallic synthesis.

Язык: Английский

Процитировано

1
HFIP‐Mediated Dual C(Ar)‐Alkylation Process towards the Regioselective Synthesis of Triarylmethanes (TRAMs) DOI

Yaqoob A. Teli,

Reetu Reetu,

S. Aleena Chanu

и другие.

Chemistry - An Asian Journal, Год журнала: 2024, Номер 19(21)

Опубликована: Авг. 7, 2024

The distinct roles of different chemical species are essential for the discovery novel transformations in organic synthesis. Here, we have designed a potential strategy synthesis triarylmethanes (TRAMs) using dual C(aryl)-alkylation process. This protocol was influenced by 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as pivotal reagent and proceeds through selective para C-H functionalization method. described approach has been proven to be highly efficient terms substrate scope with excellent functional group tolerance gram scale desired product 90 % yield. recyclability reusability HFIP enhanced feasibility this towards sustainable TRAMs.

Язык: Английский

Процитировано

1