A versatile, inexpensive and sustainable protocol for the preparation of valuable bis-indolyl methanes visible light-mediated, metal-free Friedel-Crafts arylation has been developed. The procedure, that exploits the peculiar behavior of arylazo sulfones as non-ionic photoacid generators (PAGs), was applied to the conversion of a variety of aliphatic and aromatic aldehydes into diarylmethanes in good to highly satisfactory yields, employing a low-catalyst loading (0.5 mol%) and irradiation at 456 nm.
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http://dx.doi.org/10.1039/d2ob02214a | DOI Listing |
Chem Asian J
November 2024
Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China.
Since the initial report, the Friedel-Crafts reaction has become a powerful tool to functionalize arenes. Nevertheless, the use of nitrogen heterocycles as electrophiles in Friedel-Crafts reactions has been less explored. Here, we show a Friedel-Crafts-like reaction of electron-rich arenes with quinazolin-4(3H)-ones, enabling late-stage C2-H arylation of quinazolin-4(3H)-ones via triflic anhydride (TfO) activation.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.
In this report, we detail two distinct synthetic approaches to calyciphylline A-type alkaloids himalensine A and daphenylline, which are inspired by our analysis of the structural complexity of these compounds. Using MolComplex, a Python-based web application that we have developed, we quantified the structural complexity of all possible precursors resulting from one-bond retrosynthetic disconnections. This led to the identification of transannular bonds as especially simplifying to the molecular graph, and, based on this analysis, we pursued a total synthesis of himalensine A from macrocyclic intermediates with planned late-stage transannular ring formations.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
Sulfur functional groups are ubiquitous in molecules used in the pharmaceutical and agrochemical industries, and within these collections sulfones hold a prominent position. The double aza-analogues of sulfones, sulfondiimines, offer significant potential in discovery chemistry but to date their applications have been limited by the lack of convenient synthetic routes. The existing methods mainly rely on imination of low-valent-sulfur intermediates, or the combination of pre-formed organometallic reagents and electrophilic S(VI)-functionalities.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
AnHui Province Key Laboratory of Optoelectronic and Magnetism Functional Materials, School of Chemistry and Chemical Engineering, Anqing Normal University, Anqing 246011, China. Electronic address:
Although progress has been made in the development of hypercrosslinked polymers (HCPs) for iodine uptake, their fluorescence performance and fluorescence sensing performance are rare due to the lack of conjugated behavior in common HCPs. Herein, the N,N,N',N'-tetraphenylbenzidine-based conjugated hyper-crosslinked polymers (conjugated TPB-based HCPs) were efficiently fabricated via a one-step Friedel-Crafts arylation reaction by selecting N,N,N',N'-tetraphenylbenzidine (TPB) and N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (DPDB) as the basic building blocks and p-dimethoxybenzene (DMB) as an external crosslinker which will lead to the formation of the conjugated structures. The derived TPB-based HCPs (denoted as, TPB-DMB and DPDB-DMB) possessed excellent stability and high surface areas, Their iodine adsorption capacities are up to 4.
View Article and Find Full Text PDFChem Commun (Camb)
September 2024
Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
A metal-free strategy has been developed for the α-arylation of carboxylic acids, secondary amides, and esters employing arenes as key reagents. This process entails the Lewis-acid catalyzed reductive Friedel-Crafts alkylation of arenes utilizing α-ketoacids, facilitated by silane in HFIP solvent. The transformation exhibits exceptional functional group tolerance, enabling late-stage functionalization of natural products.
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