Theory of Organocopper‐Mediated Reactions

Abstract

Introduction Structure and Reactivity of Organocopper Compounds Conjugate Addition versus S N 2 Alkylation Reactions Allylation, Alkenylation and Acylation Reactions Effect of L ewis Acid and L ewis Base Concluding Remarks

Probing Cyanocuprates by Electrospray Ionization Mass Spectrometry

“…For sample solutions containing CuCN/2 RLi, only cyanide-free anions of the type Li n −1 Cu n R 2 n − are observed. This finding completely agrees with the current consensus that diorganocuprates do not form higher-order complexes to a measurable extent (see above). − Sample solutions prepared from CuCN/RLi display a greater manifold of cuprate anions, with Li n −1 Cu n R n (CN) n − complexes being most prominent. The stoichiometry of these species reflects the nominal overall composition of the solution.…”

“…In a detailed study on a series of mixed cuprates Cu(Me)R − , Rijs and O’Hair very recently have obtained similar findings by a combination of gas-phase experiments and theoretical calculations . The comparison between mono- and polynuclear cuprates shows how the higher complexity of the latter opens up additional reaction channels; a similar situation is found for the bimolecular reactivity of lithium organocuprates . The different deaggregation processes observed for the polynuclear complexes also include the elimination of MeLi from LiCu 2 Me 4 − (Table , entry 2b), which deserves particular attention, as it is the only fragmentation reaction producing an organolithium compound.…”

“…The high reactivity of cyanocuprates has provoked numerous mechanistic and structural investigations. − In particular, the binding site of the cyanide anion has been discussed controversially. Originally, Lipshutz and co-workers postulated the formation of so-called higher-order diorganocuprates Li 2 CuR 2 (CN), in which the CN − ions coordinate to the Cu centers. , On the basis of 13 C NMR and X-ray absorption spectroscopic measurements as well as on theoretical calculations, respectively, Bertz and others challenged this view and instead proposed the existence of lower-order diorganocuprates LiCuR 2 ·LiCN.…”

Regio- and Stereocontrol in the Reactions of α-Halo-β,γ-enoates and α-O-Phosphono-β,γ-enenitriles with Organocuprates

“…The primary control element in cuprate -mediated allylic substitution reactions is the preference for anti-S N 2′-substitution pathways, which are enhanced by use of alkyl- or aryl(cyano)cuprate reagents, , magnesium cuprates, , and phosphate leaving groups . The greater S N 2′-regioselectivity observed for RCuCNLi reagents has been attributed to a trans effect with the more electron rich R-group on the cuprate reagent preferring (i.e., lower transition state energy) to be trans to the substrate leaving group (cf.…”

Modeling Solvation of Magnesium Centers by Ether Ligands: Gas-Phase Synthesis and Hydrolysis of the Organomagnesium Cations [CH3Mg(3X-crown-X)]+(X= 4–6)

“…Two key “textbook” organometallic reagents that we have tried to develop gas-phase models for are Gilman reagents, R 2 CuLi, and Grignard reagents, RMgL (where L is typically a halide such as chloride) . Since mass spectrometers can only isolate and detect ions, these gas-phase studies require the design of organometallic complexes that possess an overall charge.…”