Copper-catalyzed radical cascades of para-quinone methides with AIBN and HO via α-cyanoalkylation by C-C bond cleavage: new access to benzofuran-2(3H)-ones.

Chem Commun (Camb)

Hunan Engineering Laboratory of Analysis and Drugs Development of Ethenomedicine in Wuling Mountain, Jishou University, Jishou 416000, China.

Published: April 2019


Category Ranking

98%

Total Visits

921

Avg Visit Duration

2 minutes

Citations

20

Article Abstract

We describe the first one-pot construction of a benzofuran-2(3H)-one scaffold via a radical cascade reaction of para-quinone methides with azodiisobutyronitrile and water. In the presence of CuI (20 mol%), this cascade proceeds smoothly through 1,6-conjugate addition/aromatization, α-cyanoalkylation by unstrained and non-polar C(aryl)-C(t-butyl) bond cleavage, and downstream cyano-insertion/cyclization/hydrolysis, which leads to cyano-containing benzofuran-2(3H)-ones with an excellent functional-group compatibility.

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cc00294dDOI Listing

Publication Analysis

Top Keywords

para-quinone methides
8
bond cleavage
8
copper-catalyzed radical
4
radical cascades
4
cascades para-quinone
4
methides aibn
4
aibn α-cyanoalkylation
4
α-cyanoalkylation c-c
4
c-c bond
4
cleavage access
4

Similar Publications

Among various treatment options for diabetes, insulin therapy remains an important approach, but it inevitably carries the risk of hypoglycaemia, particularly due to dosing errors or unexpected glucose fluctuations. To address this challenge, glucose-responsive insulin delivery systems that release insulin based on blood glucose levels have emerged as a promising solution. In this study, we developed a fully dissolved glucose-responsive insulin delivery system using -borono-phenylmethoxycarbonyl-modified insulin aspart (BPmoc-Ins-Asp) and glucose oxidase (GOx).

View Article and Find Full Text PDF

Herein, we demonstrate a [2+2] cycloaddition/electrocyclic ring-opening reaction between quinone methide and electronically unbiased terminal alkynes under strictly thermal conditions. The present investigation is a unique example that demonstrates the effect of extended conjugation and cross-conjugation on the energy of the lowest unoccupied molecular orbital. As supported by density functional theory calculations, the reaction proceeds through the biradical pathway, accommodating both electron-deficient and electron-rich alkyne partners.

View Article and Find Full Text PDF

We report a visible-light-driven asymmetric three-component reaction enabling direct enantioselective C2-functionalization of indoles. This method utilizes arylalkynes, benzoquinones, and indoles under chiral phosphoric acid catalysis to construct chiral indole derivatives bearing all-carbon quaternary stereocenters. The reaction proceeds via a cascade sequence: (1) Paternò-Büchi [2 + 2] cycloaddition between arylalkynes and benzoquinones, (2) electrocyclic ring-opening to generate para-quinone methide intermediates, and (3) enantioselective 1,6-addition of indoles at C2 to the para-quinone methide.

View Article and Find Full Text PDF

Displaying versatile biological activity, Schiff bases are known to possess prominent optical, thermal, and metal coordination properties, rendering them prospective for the design of dyes, photonic devices, ion sensors, molecular probes, etc. Furthermore, azomethine compounds bearing a phenolic moiety may exert antioxidant action. In this work, the antioxidant activity of the bis-substituted and mono-substituted phenolic azomethine dyes derived from 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde was determined in DPPH radical and ABTS cation radical scavenging assays, FRAP and CUPRAC metal reducing assays, and ferrous iron chelating activity assay.

View Article and Find Full Text PDF

Synthesis and Trapping of the Elusive -Iminoquinone Methide Derived from α-Tocopheramine and Comparison to the Case of α-Tocopherol.

Molecules

August 2025

Department of Natural Sciences and Sustainable Resources, Institute of Chemistry of Renewable Resources, BOKU University, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria.

Tocopheramines are a class of antioxidants which are distinguished from tocopherols (vitamin E) by the presence of an amino group instead of the phenolic hydroxyl group. α-Tocopheramine is intensively studied for biomedical applications but also as a stabilizer for synthetic and natural polymers, in particular for cellulose solutions and spinning dopes for cellulosic fibers. This study addresses a fundamental difference in the oxidation chemistry of α-tocopheramine and its tocopherol counterpart: while the formation of the ortho-quinone methide (o-QM) involving C-5a is one of the most fundamental reactions of α-tocopherol, the corresponding ortho-iminoquinone methide (o-IQM) derived from α-tocopheramine has been elusive so far.

View Article and Find Full Text PDF