Organolithium compounds are often depicted as mononuclear species. However, such compounds are in fact aggregated species and can form hetero-aggregates containing different organic groups, including heteroatom groups. In reactions involving organolithium reagents, the "pure" homo-aggregate organolithium compound can change into a hetero-aggregate, which has a different structure and reactivity to the homo-aggregate. This fact is often overlooked. When there are chiral centers in the organolithium reagent or the substrate, diastereoselective self-assembly (the preferential formation of a particular diastereoisomeric aggregate) plays a role. The importance of these contributions in understanding the structure and reactivity patterns of organolithium reagents is the focus of this Minireview.
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http://dx.doi.org/10.1002/anie.200462103 | DOI Listing |
Angew Chem Int Ed Engl
December 2024
Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 2, Singapore, 117543, Singapore.
Asymmetric synthesis relies on seamless transmission of stereochemical information from a chiral reagent/catalyst to a prochiral substrate. The disruption by substrates' structural changes presents a hurdle in innovating generality-oriented asymmetric catalysis. Here, we report a strategy for substrate adaptability by exploiting a fundamental physicochemical phenomenon-ion hydration, in developing remote desymmetrization to access P-stereogenic triarylphosphine oxides and sulfides.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Université de Reims Champagne-Ardenne, CNRS, ICMR, Reims, France.
A strategy for the synthesis of 1--substituted thioglycals was developed from cyclic carbohydrate-derived ketene dithioacetals in a four-step sequence. The corresponding thioglycals, in two carbohydrate series, were first obtained by removal of the exocyclic glycosyl sulfoxide, followed by treatment with an organolithium reagent. Various electrophilic groups were introduced onto the thioglycal double bond after deprotonation and formation of a glycosyl lithium intermediate.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Chinese Academy of Sciences), Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, 200032, Shanghai, China.
Organolithium reagents, known for their low cost, ready availability, and high reactivity, allow fast cross-coupling under ambient conditions. However, their direct cross-coupling with fluoroalkyl electrophiles remains a formidable challenge due to the easy formation of thermo-unstable fluoroalkyl lithium species during the reaction, which are prone to decomposition via rapid α/β-fluoride elimination. Here, we exploit heteroatom-stabilized allylic anions to harness the exceptional reactivity of organolithium reagents, enabling the compatibility of difluoroalkyl halides and facilitating versatile and precise fluorine functionality introduction under mild conditions.
View Article and Find Full Text PDFChemSusChem
November 2024
Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland.
Advancing the use of air-sensitive polar organometallic Grignard and organolithium reagents under more environmentally benign conditions, here we report the addition of these reagents to α,β-unsaturated ketones and aldehydes using the deep eutectic solvent (DES) choline chloride (ChCl): glycerol (Gly) (1 : 2), under air. Reactions occur at room temperature within seconds with excellent regioselective control. Furthering understanding of how these C-C bond forming processes take place in these reaction media, we have explored the surface concentration of the organic substrate (chalcone) in DES using interfacial tension and neutron reflectivity measurements, finding that chalcone is concentrated at the DES-hydrocarbon interface compared to the bulk concentration, although the interfacial chalcone concentration is still relatively low in this system.
View Article and Find Full Text PDFChemistry
November 2024
Institute of Organic Chemistry, University of Regensburg, D-93053, Regensburg, Germany.
Non-covalent interactions, including the coordination of an organolithium reagent by a directing group and the steric hindrance from substituents, play a crucial role in determining the selectivity of metalation reactions. Here, we demonstrate the effective utilization of steric interactions for flipping the lithiation of 4-dimethylaminopyridine (DMAP). Introduction of a MeSi substituent to the position 1 of DMAP or simple complexation with t-BuLi allows selective C3-lithiation, due to the steric hindrance of a C2-H bond by the bulky moiety at the pyridine nitrogen.
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