Reactions with lithium dimethylcuprate and lithium dimethylaurate

Hallnemo, Gerd; Ullenius, Christina

doi:10.1016/s0040-4020(01)88572-0

Cited by 49 publications

(15 citation statements)

References 32 publications

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“…Although not routine, this Cu(I)-catalyzed reactions can be carried out in solvents such as Et 2 O, toluene, dichloromethane or THF. [15] Et 2 O is the solvent of choice for this asymmetric addition reScheme 1. Synthesis of sulfonamide-thiophosphoramide ligands L1 -L7.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric 1,4-Addition of Diethylzinc to Cyclic Enones Catalyzed by Cu(I)-Chiral Sulfonamide-Thiophosphoramide Ligands and Lithium Salts

Shi¹,

Zhang²

2005

Advanced Synthesis & Catalysis

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The chiral sulfonamide-thiophosphoramide ligand L1, prepared from the reaction of (1R,2R)-(À)-1,2-cyclohexanediamine with diphenylthiophosphoryl chloride and p-toluenesulfonyl chloride, was used as a chiral ligand in Cu(MeCN) 4 ClO 4 -promoted catalytic asymmetric addition of diethylzinc to cyclic enones using LiCl as an additive in which up to 90% ee can be realized under mild conditions within 0.5 h. This chiral ligand is stable and recoverable after usual work-up and can be reused in the same catalytic asymmetric reaction. Moreover, it was found that this series of chiral ligands represents a type of S,O-bidentate ligands on the basis of 1 H NMR, 31 P NMR and 13 C NMR spectroscopic investigations. The linear effect of ligand ee and product ee further revealed that the active species is a monomeric Cu(I) complex bearing a single ligand.

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Section: Resultsmentioning

confidence: 99%

Asymmetric 1,4-Addition of Diethylzinc to Cyclic Enones Catalyzed by Cu(I)-Chiral Sulfonamide-Thiophosphoramide Ligands and Lithium Salts

Shi¹,

Zhang²

2005

Advanced Synthesis & Catalysis

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“…In addition, the Cu 1 atom is datively coordinated by the C 1 C 2 p bond of the enolate. [17,44] The formation of the product PD is a highly exothermic process.…”

Section: Resultsmentioning

confidence: 99%

Density Functional Studies on Conjugate Addition of (Me2CuLi)2 to Cyclohexenone: Stereoselectivity and Rate-Determining Step

Mori

Nakamura

1999

Chem. Eur. J.

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The reaction pathway of the conjugate addition of a dimeric cuprate (Me 2 CuLi) 2 to 2-cyclohexenone has been studied by means of the B3LYP hybrid density functional method, and intermediates and transition structures (TSs) on the potential surface of the reaction have been determined. A lithium/carbonyl coordination complex (CPli), a copper/olefin complex retaining a closed cuprate structure (CPcl), a copper/olefin complex with an open cuprate structure (CPop), and the TS of CÀC bond formation (TScc) have been located along the gas-phase pathway leading to the conjugate addition product (PD). We studied two diastereoisomeric pathways, and found that the pathway that results in the axial placement of the nucleophilic methyl group in the product was favored throughout the course of the reaction, except in the product complex. Thus, the stereoselectivity of the conjugate addition to cyclohexenone originates from the stereochemical preference of the final, ratelimiting C À C bond formation stage that mainly reflects the steric factors in the formation of 3-methylcyclohexanone enolate in its half-chair form (TSccax).Comparison of the calculated and experimental values for 13 C NMR chemical shift and kinetic isotope effects strongly suggests that the copper/olefin complex of the CPop structural type is the reactive intermediate that directly forms the product. Thus, the open complex CPop, rather than the closed complex CPcl hitherto considered, is a direct precursor of the product and crucial for the stereoselectivity of the conjugate addition. On the basis of theory and experiments, transition-state models for the conjugate addition to substituted cyclohexenones are provided.

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“…This may be partly due to accelerated cluster reorganization or to coordination of lithium halide to a Cu III intermediate, which is formed during nucleophilic reactions. In the light of contrasting reports (one reports slower conjugate addition in THF than in diethyl ether, [141] another reports a faster reaction in toluene, [142] and the further one reports that 1,4-addition in toluene can be promoted over 1,2-addition in the presence of Me 2 S [143] ), solvent effects are a difficult subject to deal with.…”

Section: E Nakamura and S Morimentioning

confidence: 99%

Wherefore Art Thou Copper? Structures and Reaction Mechanisms of Organocuprate Clusters in Organic Chemistry

Nakamura

Mori

2000

Angew. Chem. Int. Ed.

270

186

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Organocopper reagents provide the most general synthetic tools in organic chemistry for nucleophilic delivery of hard carbanions to electrophilic carbon centers. A number of structural and mechanistic studies have been reported and have led to a wide variety of mechanistic proposals, some of which might even be contradictory to others. With the recent advent of physical and theoretical methodologies, the accumulated knowledge on organocopper chemistry is being put together into a few major mechanistic principles. This review will summarize first the general structural features of organocopper compounds and the previous mechanistic arguments, and then describe the most recent mechanistic pictures obtained through high‐level quantum mechanical calculations for three typical organocuprate reactions, carbocupration, conjugate addition, and SN2 alkylation. The unified view on the nucleophilic reactivities of metal organocuprate clusters thus obtained has indicated that organocuprate chemistry represents an intricate example of molecular recognition and supramolecular chemistry, which chemists have long exploited without knowing it. Reasoning about the uniqueness of the copper atom among neighboring metal elements in the periodic table will be presented.

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Reactions with lithium dimethylcuprate and lithium dimethylaurate

Cited by 49 publications

References 32 publications

Asymmetric 1,4-Addition of Diethylzinc to Cyclic Enones Catalyzed by Cu(I)-Chiral Sulfonamide-Thiophosphoramide Ligands and Lithium Salts

Asymmetric 1,4-Addition of Diethylzinc to Cyclic Enones Catalyzed by Cu(I)-Chiral Sulfonamide-Thiophosphoramide Ligands and Lithium Salts

Density Functional Studies on Conjugate Addition of (Me2CuLi)2 to Cyclohexenone: Stereoselectivity and Rate-Determining Step

Wherefore Art Thou Copper? Structures and Reaction Mechanisms of Organocuprate Clusters in Organic Chemistry

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