Regioselective bromine-lithium exchange reactions on polybrominated biaryls enable the modular synthesis of various polysubstituted biphenyls such as bis(dialkylphosphino)-, bis(diarylphosphino)- and dialkyl(diaryl)phosphinobiphenyls. All permutations of substituents at the ortho positions of the biphenyls are possible. In a similar manner, one can gain access to monophosphine analogues. So far, such a process, based on the effective discrimination between bromine atoms as a function of their chemical environment, has been observed only sporadically.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182437 | PMC |
| http://dx.doi.org/10.3762/bjoc.7.148 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
"Buttressing Effect" in the Halogen-Lithium Exchange in ortho-Bromo-N,N-dimethylanilines and Related Naphthalenes.
Chemistry
March 2024
Institute of Organic Chemistry, University of Regensburg, D-93053, Regensburg, Germany.
Non-covalent interactions such as coordination of an organolithium reagent by a directing group and steric repulsion of substituents strongly affect the halogen-lithium exchange process. Here we present the manifestation of the "buttressing effect" - an indirect interaction between two substituents issued by the presence of a third group - and its influence on the ease and selectivity of the bromine-lithium exchange and the reactivity of formed aryllithiums. The increase of the size of the "buttressing" substituent strongly affects the conformation of a NMe group, forcing it to hinder ortho-bromine and thus slowing down the exchange.
View Article and Find Full Text PDFThe Role of Conjugation in the Halogen-Lithium Exchange Selectivity: Lithiation of 4,6,7,9-Tetrabromo-1,3-dimethyl-2,3-dihydro-1H-perimidine.
Chemistry
August 2023
Institute of Organic Chemistry, University of Regensburg, D-93053, Regensburg, Germany.
The first case of successful suppression of the coordination of a lithium atom with a dialkylamino group by the effective conjugation of the latter with the aromatic core has been discovered. This effect controls regioselectivity of the bromine-lithium exchange in 4,6,7,9-tetrabromo-1,3-dimethyl-2,3-dihydro-1H-perimidine, which leads to products with the most effective conjugation. As a result, the product of this quadruple exchange demonstrates no tendency of the coordination of the NMe groups to neighboring lithium atoms despite the absence of steric restrictions.
View Article and Find Full Text PDF3-Ligated Phenothiazinyl-terephthalonitrile Dyads and Triads - Synthesis, Electronic Properties, Delayed Fluorescence and Electronic Structure.
Chemistry
August 2023
Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
The bromine-lithium exchange-borylation-Suzuki sequence efficiently furnishes phenothiazine-terephthalonitrile donor-acceptor dyads and triads in high yields. In contrast to most phenothiazine-acceptor conjugates the title compounds are ligated in p-position to the phenothiazine nitrogen atom. Moreover, the acceptors are either directly linked or ligated by an arylene bridge and p-anisyl N-substituents on the phenothiazine are chosen to lock the tricycle into an intra-configuration.
View Article and Find Full Text PDFOrganogel delivery vehicles for the stabilization of organolithium reagents.
Nat Chem
March 2023
Department of Chemistry, University of York, York, UK.
Organolithium reagents are a vital tool in modern organic chemistry, enabling the synthesis of carbon-carbon bonds. However, due to their high reactivity, low temperatures, inert atmospheres and strictly dried solvents are usually necessary for their use. Here we report an encapsulating method for the stabilization of sensitive organolithium reagents-PhLi, n-BuLi and s-BuLi-in a low-cost hexatriacontane (CH) organogel.
View Article and Find Full Text PDFHighly Deep-Blue Luminescent Twisted Diphenylamino Terphenyl Emitters by Bromine-Lithium Exchange Borylation-Suzuki Sequence.
Chemistry
May 2022
Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225, Düsseldorf, Germany.
Four novel intensively blue luminescent chromophores were readily synthesized by bromine-lithium exchange borylation-Suzuki (BLEBS) sequence in moderate to good yields. Their electronic properties were studied by absorption and emission spectroscopy and quantum chemical calculations revealing deep-blue emission in solution as well as in the solid state and upon embedding into a PMMA (polymethylmethacrylate) matrix with small FWHM (full width at half maximum) values and CIE y values smaller than 0.1.
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!