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The classical 1,3-dipolar cycloaddition reaction predominantly generates five-membered heterocycles through cycloaddition between 1,3-dipoles and unsaturated hydrocarbons, such as alkenes or alkynes. Herein, we report a light-mediated approach that employs saturated amines as alternatives to conventional unsaturated hydrocarbons, enabling their reaction with -imino(iso)quinolinium ylides to achieve efficient synthesis of pyrazolo-fused (iso)quinoline core structures. This method demonstrates operational simplicity, mild reaction conditions, and excellent functional group compatibility. Mechanistic investigations reveal that the -imino(iso)quinolinium ylides not only serve as substrates but also function as photosensitizers, facilitating the formation of critical pyrazolo-fused (iso)quinoline structural units through the single-electron oxidation of amines to generate enamine intermediates.
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http://dx.doi.org/10.1021/acs.orglett.5c02268 | DOI Listing |
Chem Sci
November 2024
State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University Changsha Hunan 410082 P. R. China
Although cycloadditions of bicyclobutanes (BCBs) have emerged as a reliable approach for producing bicyclo[.1.1]alkanes such as azabicyclo[3.
View Article and Find Full Text PDFChem Commun (Camb)
September 2022
Jiangsu Key Laboratory of Advanced Catalytic Materials & Technology, School of Petrochemical Engineering, Changzhou University, Changzhou, China.
A new approach for the synthesis of 9-membered N,N,O-heterocycles by Pd-catalyzed [6+3] dipolar cycloaddition of -iminoisoquinolinium ylides and 2-vinyl oxetanes has been developed. The scope of this cycloaddition was demonstrated with 28 examples. This is another important synthetic strategy for medium-sized rings by employing -iminoisoquinolinium ylides as ternary synthons.
View Article and Find Full Text PDFJ Org Chem
April 2018
University of Chinese Academy of Sciences, No. 19A Yuquan Road , Beijing 100049 , China.
The dearomatizing annulation reaction is a significant challenge in organic chemistry. The direct activation of α-carbons of simple saturated esters, as nucleophiles, is an important synthesis strategy. In the present study, we disclose [3 + 2] dearomatizing annulation reactions with direct activating α-carbons of saturated carboxylic esters and N-iminoisoquinolinium ylides, which possess highly enantioselective characteristics, catalyzed by N-heterocyclic carbenes (NHCs).
View Article and Find Full Text PDFNat Chem
October 2015
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, Münster 48149, Germany.
The development of general catalytic methods for the regio- and stereoselective construction of chiral N-heterocycles in a diversity-oriented fashion remains a formidable challenge in organic synthesis. N-heterocyclic carbene (NHC) catalysis has been shown to produce a variety of outcomes, but control of the reactivity has rarely been demonstrated. Here we report a switchable catalytic activation of enals with aromatic azomethine imines that provides high selectivity using NHC organocatalysts.
View Article and Find Full Text PDFJ Org Chem
September 2012
Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Chemistry & Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People's Republic of China.
Silver triflate and copper(I) iodide cocatalyzed direct alkynylation and cyclization reaction of in situ formed N-iminoisoquinolinium ylides with bromoalkynes is described. The reaction proceeds efficiently through a combination of C-H activation and subsequent tandem reaction in one pot, leading to diverse H-pyrazolo[5,1-a]isoquinolines in good yields under mild reaction conditions.
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