Organocatalytic Synthesis of Chiral Halogenated Compounds

The Chemical Record, Journal Year: 2023, Volume and Issue: 23(7)

Published: April 12, 2023

Abstract This account summarizes our recent efforts in the enantioselective organocatalytic synthesis of chiral halogenated compounds. The α‐halogenation aldehydes, decarboxylative chlorination β‐keto acids, and C−C bond formation at trifluoromethylated prochiral carbon to yield corresponding organohalides with chlorinated, fluorinated, or stereogenic centers are discussed. We applied common organocatalysts, such as Jørgensen‐Hayashi catalyst cinchona alkaloid‐derivatived catalyst, developed novel amine catalysts for these reactions. also discusses stereospecific derivatizations resulting compounds via nucleophilic substitution. Thus, we synthesized many that have not been reported, even racemates.

Language: Английский

---

Bis-Thiourea Chiral Sensor for the NMR Enantiodiscrimination of N-Acetyl and N-Trifluoroacetyl Amino Acid Derivatives

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(18), P. 11968 - 11978

Published: Sept. 5, 2022

A C2-symmetrical bis-thiourea chiral solvating agent (CSA), TFTDA, for NMR spectroscopy has been obtained by reacting (1R,2R)-1,2-bis(2-hydroxyphenyl)ethylenediamine and 3,5-bis(trifluoromethyl)phenyl isothiocyanate. TFTDA shows remarkable propensity to enantiodiscriminate N-trifluoroacetyl (N-TFA) N-acetyl (N-Ac) derivatives of amino acids with free carboxyl functions, the co-presence 1,4-diazabicyclo[2.2.2]octane (DABCO) as third achiral additive, which is needed substrate solubilization. enhanced enantiodiscriminating efficiency in comparison corresponding monomeric counterpart, TFTMA, pointing out cooperativity between its two symmetrical entities. wide range acid have efficiently enantiodiscriminated CDCl3, high enantioresolution quotients, guarantee quality applications devoted quantification enantiomers. High maintained also diluted 5 mM conditions or presence sub-stoichiometric amounts CSA (0.3 equiv). The role phenolic hydroxyls DABCO-mediated interaction mechanism enantiomeric substrates pointed means diffusion-ordered (DOSY) rotating frame Overhauser effect (ROESY) experiments. conformational model both diastereomeric solvates formed enantiomers leucine conceived on basis ROE data order give a discrimination rationale.

Language: Английский

---

Enantioselective halogenation via asymmetric phase‐transfer catalysis

Bulletin of the Korean Chemical Society, Journal Year: 2022, Volume and Issue: 43(7), P. 896 - 911

Published: June 2, 2022

Abstract The asymmetric phase‐transfer catalysis (PTC) is a flourishing field of contemporary synthetic organic chemistry, and this prominent methodology has been tremendously successful in enantioselective halogenations. Both electrophilic nucleophilic reaction manifolds were enabled through the exploitation highly ordered ion pairing and/or hydrogen‐bonding interactions around carefully designed chiral catalyst with an insoluble halogenating reagent as well suitable substrate. Fluorination most fruitful, encouraging results have also documented heavier halogens. This review surveys examples various halogenations via PTC from its beginning to prosperity over past decade.

Language: Английский

---

Asymmetric Synthesis of Chiral α‐CF₂H Spiro[Indoline‐3,3′‐Thiophene] via Phase‐Transfer Catalyzed Sulfa‐Michael/Michael Domino Reaction

Advanced Synthesis & Catalysis, Journal Year: 2021, Volume and Issue: 364(4), P. 811 - 830

Published: Dec. 16, 2021

Abstract An asymmetric Sulfa‐Michael/Michael domino reaction of ( E )‐4‐mercapto‐2‐butenoates with difluoromethyl‐eneoxindoles catalyzed by a quinidine‐derived ammonium salts as phase transfer catalyst has been disclosed. Under mild conditions, broad range CF 2 H‐containing spiro[indoline‐3,3′‐thiophene]s, bearing three adjacent chiral centers including two vicinal spiro quaternary stereocenters, catalysed only 5 mol% PTC were obtained in yields 75–98%, excellent diastereoselectivities (>20:1, almost all cases) and enantioselectivities 19–98% short times (almost less than 20 minutes). magnified image

Language: Английский

---

Radical Cyclization of N-Methacryloyl-2-arylbenzoimidazoles with Nitriles, Ketones, and tert-Butyl Nitrite under Mild Conditions

Synthesis, Journal Year: 2022, Volume and Issue: 54(23), P. 5233 - 5244

Published: July 3, 2022

Abstract A method for radical cyclization of N-methacryloyl-2-arylbenzoimidazoles with nitriles, ketones, and tert-butyl nitrite (TBN) the preparation benzimidazo[2,1-a]isoquinolin-6(5H)-ones advantage mild reaction conditions, excellent functional group compatibility, broad substrate scope is reported. The present strategy has favorable characteristics: (1) use cheap metal catalysis; (2) N-radical-initiated N-methacryloyl-2-arylbenzoimidazoles; (3) rare example C(sp3)–H functionalization in this cyclization.

Language: Английский

---

Domino reactions of thiopyrano[4,3-b]indole-3(5H)-thiones and dimethyl acetylenedicarboxylate: Quantum chemical investigation and experiment

Journal of Sulfur Chemistry, Journal Year: 2022, Volume and Issue: 44(2), P. 248 - 259

Published: Oct. 28, 2022

Reaction of thiopyrano[4,3-b]indole-3(5H)-thiones and dimethyl acetylenedicarboxylate (DMAD) proceeds via two competing cascade pathways. Initially, both the pathways begin from thiocarbonyl sulfur acetylene carbon atoms interaction. Then parallel processes take place: an alkyne–thiocarbonyl metathesis a (3 + 2) cycloaddition. In next stages, in cases, thiophene ring formation thiopyran opening proceed. Finally, (4 cycloaddition reactions intermediate thioketones second equivalent DMAD leads to resulting thiopyrano[4,3-b]indole derivatives bearing thienyl substituent. The kinetic thermodynamic characteristics were compared on basis DFT ab initio 6-311++G(d,p) quantum chemical calculations.

Language: Английский

---

Selectfluor and alcohol-mediated synthesis of bicyclic oxyfluorination compounds by Wagner–Meerwein rearrangement

Beilstein Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 20, P. 1462 - 1467

Published: July 1, 2024

Herein, we report the first environmentally friendly systematic fluoroalkoxylation reactions in bicyclic systems. New oxyfluorination products were obtained with excellent yields (up to 98%) via Wagner–Meerwein rearrangement using benzonorbornadiene and chiral natural compound (+)-camphene as alkenes, selectfluor an electrophilic fluorine source, water various alcohols nucleophile sources. The structure of oxy- alkoxyfluorine compounds was determined by NMR QTOF-MS analyses.

Language: Английский

---

Spectroscopic Analysis: NMR and Shift Reagents

Elsevier eBooks, Journal Year: 2022, Volume and Issue: unknown, P. 560 - 592

Published: Sept. 9, 2022

Language: Английский

---

Domino Reactions of Thiopyrano[4,3-B]Indole-3(5h)-Thiones and Dimethyl Acetylenedicarboxylate: Quantum Chemical and Experimental Data

SSRN Electronic Journal, Journal Year: 2022, Volume and Issue: unknown

Published: Jan. 1, 2022

Reaction of thiopyrano[4,3- b ]indole-3(5 H )-thiones and dimethyl acetylenedicarboxylate proceed via two competing cascade pathways. Both mechanisms have been investigated in detail by DFT PCM/B3LYP/6-311++G(d,p) quantum chemical calculations. Initially, the reactions occur an alkyne–thiocarbonyl metathesis or (3+2) cycloaddition mechanisms. At next stages, parallel rearrangements both cases proceed, including thiopyrane rings opening thiophene closure. Cycloaddition processes intermediate thioketones a second equivalent DMAD leads to resulting ]indole derivatives bearing thienyl substituent.

Language: Английский

---