2,2,6,6-Tetramethylpiperidine (TMP)-catalyzed (1-10%) chlorinations of phenols by SO2Cl2 in aromatic solvents are more ortho selective than with primary and less hindered secondary amine catalysts. Ortho-selective chlorination is successful even with electron deficient phenols such as 2-hydroxybenzaldehyde and 2'-hydroxyacetophenone. Notably, ortho selectivity increases with the reaction temperature. On the other hand, tetraalkylammonium chloride-catalyzed chlorinations are moderately para selective.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jo402424h | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Amine organocatalysts for highly -selective chlorination of anilines with sulfuryl chloride.
Chem Commun (Camb)
December 2022
School of Pharmacy, Nanchang University, Nanchang, Jiangxi, 330006, China.
A metal catalyst free approach for regioselective -chlorination of anilines has been developed using a secondary amine as the organocatalyst and sulfuryl chloride as the halogen source under mild conditions. A wide range of substrates were compatible with this catalytic system. In addition, this catalytic protocol has been applied to the efficient synthesis of bioactive compounds and modification of drug derivatives.
View Article and Find Full Text PDFAmine-Directed Palladium-Catalyzed C-H Halogenation of Phenylalanine Derivatives.
Chemistry
October 2021
Normandie Université, UNIROUEN, INSA Rouen, CNRS, COBRA, 76000, Rouen, France.
An efficient primary-amine-directed, palladium-catalyzed C-H halogenation (X=I, Br, Cl) of phenylalanine derivatives is reported on a range of quaternary amino acid (AA) derivatives thanks to suitable conditions employing trifluoroacetic acid as additive. The extension of this original native functionality-directed ortho-selective halogenation was even demonstrated with the more challenging native phenylalanine as tertiary AA.
View Article and Find Full Text PDFPalladium-Catalyzed Weakly Coordinating Lactone-Directed C-H Bond Functionalization of 3-Arylcoumarins: Synthesis of Bioactive Coumestan Derivatives.
J Org Chem
July 2021
Department of Chemistry, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India.
A palladium-catalyzed highly regioselective -selective C-H functionalization of 3-arylcoumarins has been developed. The method utilizes the weakly coordinating lactone as a directing group. The versatility of the strategy is highlighted by developing methodologies for alkenylation, halogenation, fluoroalkoxylation, and hydroxylation.
View Article and Find Full Text PDFEnantioselective Total Synthesis of (-)-Spiroxins A, C, and D.
Angew Chem Int Ed Engl
August 2021
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China.
Spiroxins A, C, and D are metabolites that have been identified in the marine fungal strain LL-37H248. Their unique polycyclic structures and intriguing biological activities make them attractive targets for the synthetic community. Based on a scalable enantioselective epoxidation of 5-substituted naphthoquinone, an oxidation/spiroketalization cascade, ortho-selective chlorination of the phenol unit, and oxime-ester-directed acetoxylation, an enantioselective total synthesis of (-)-spiroxins A and C and the first total synthesis of (-)-spiroxin D have been achieved.
View Article and Find Full Text PDFCatalyst-Controlled Regioselective Chlorination of Phenols and Anilines through a Lewis Basic Selenoether Catalyst.
J Org Chem
November 2020
Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182, United States.
We report a highly efficient ortho-selective electrophilic chlorination of phenols utilizing a Lewis basic selenoether catalyst. The selenoether catalyst resulted in comparable selectivities to our previously reported bis-thiourea ortho-selective catalyst, with a catalyst loading as low as 1%. The new catalytic system also allowed us to extend this chemistry to obtain excellent ortho-selectivities for unprotected anilines.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!