Sterically Hindered Lithium Dialkylcuprates for the Generation of Highly Functionalized Mixed Cuprates through a Halogen���Copper Exchange

Piazza, Claudia; Knöchel, Paul

doi:10.1002/1521-3773(20020902)41:17<3263::aid-anie3263>3.0.co;2-8

Cited by 64 publications

(17 citation statements)

References 14 publications

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“…Quenching the organometallic reagents with various standard electrophiles provides the expected products 47 and 48 (Scheme ). Interestingly, iodine–copper exchange also gives a useful entry to polyfunctional copper reagents; however, aryl or heteroaryl iodides are always required as precursors for this exchange. ,, …”

Section: Preparation Of Polyfunctional Zinc and Magnesium Organometal...mentioning

confidence: 99%

Strategies To Prepare and Use Functionalized Organometallic Reagents

et al. 2014

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Polyfunctional zinc and magnesium organometallic reagents occupy a central position in organic synthesis. Most organic functional groups are tolerated by zinc organometallic reagents, and Csp(2)-centered magnesium organometallic reagents are compatible with important functional groups, such as the ester, aryl ketone, nitro, cyano, and amide functions. This excellent chemoselectivity gives zinc- and magnesium-organometallic reagents a central position in modern organic synthesis. Efficient and general preparations of these organometallic reagents, as well as their most practical and useful reactions, are presented in this Perspective. As starting materials, a broad range of organic halides (iodides, bromides, and also to some extent chlorides) can be used for the direct insertion of magnesium or zinc powder; the presence of LiCl very efficiently promotes such insertions. Alternatively, aromatic or heterocyclic bromides also undergo a smooth bromine-magnesium exchange when treated with i-PrMgCl·LiCl. Alternative precursors of zinc and magnesium reagents are polyfunctionalized aryl and heteroaryl molecules, which undergo directed metalations with sterically hindered TMP bases (TMP = 2,2,6,6-tetramethylpiperide) of magnesium and zinc. This powerful C-H functionalization method gives access to polyfunctional heterocyclic zinc and magnesium reagents, which undergo efficient reactions with numerous electrophiles. The compatibility of the strong TMP-bases with BF3·OEt2 (formation of frustrated Lewis pairs) dramatically increases the scope of these metalations, giving for example, a practical access to magnesiated pyridines and pyrazines, which can be used as convenient building blocks for the preparation of biologically active molecules.

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Section: Preparation Of Polyfunctional Zinc and Magnesium Organometal...mentioning

confidence: 99%

Strategies To Prepare and Use Functionalized Organometallic Reagents

et al. 2014

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“…Transmetalation provides the most straightforward and reliable method f preparing organocopper compounds from readily available organometallic reagents [19,20], though many other synthetic strategies are also known, such as copper-halide exchange reactions [21], direct cupration [22], and the oxidative addition of reactive Rieke Cu* [23]. It should be emphasized that the identity of forming organocopper compounds is very much dependent on the ratio of starting materials.…”

Section: Introductionmentioning

confidence: 99%

C,C- and C,N-Chelated Organocopper Compounds

et al. 2021

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Copper-catalyzed and organocopper-involved reactions are of great significance in organic synthesis. To have a deep understanding of the reaction mechanisms, the structural characterizations of organocopper intermediates become indispensable. Meanwhile, the structure-function relationship of organocopper compounds could advance the rational design and development of new Cu-based reactions and organocopper reagents. Compared to the mono-carbonic ligand, the C,N- and C,C-bidentate ligands better stabilize unstable organocopper compounds. Bidentate ligands can chelate to the same copper atom via η2-mode, forming a mono-cupra-cyclic compounds with at least one acute C-Cu-C angle. When the bidentate ligands bind to two copper atoms via η1-mode at each coordinating site, the bimetallic macrocyclic compounds will form nearly linear C-Cu-C angles. The anionic coordinating sites of the bidentate ligand can also bridge two metals via μ2-mode, forming organocopper aggregates with Cu-Cu interactions and organocuprates with contact ion pair structures. The reaction chemistry of some selected organocopper compounds is highlighted, showing their unique structure–reactivity relationships.

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“…The use of polyfunctional organometallic reagents for the synthesis of complex polyfunctional target molecules represents a versatile method for the selective introduction of well-defined and complex building blocks under mild conditions. 1 Various halogen-metal exchange reactions are well established and allow the preparation of functionalized organolithium, 2 organomagnesium 3 and organocopper 4 reagents. Especially organozincs are known to tolerate a wide range of functional groups.…”

Section: Introductionmentioning

confidence: 99%