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Neutral organocopper(III) complexes have been prepared from organocuprate(I) reagents and alkyl halides in the presence of certain strongly electron donating ligands.

The first pi-allyl complexes of CuIII have been prepared and characterized by using rapid injection nuclear magnetic resonance spectroscopy (RI-NMR). The prototype, (eta3-allyl)dimethylcopper(III), was prepared by injection of allyl chloride into a THF-d8 solution of iodo-Gilman reagent, Me2CuLi.LiI (A), spinning in the probe of an NMR spectrometer at -100 degreesC. A sigma-allyl ate complex, lithium (eta1-allyl)trimethylcuprate(III), was prepared in high yield by including 1 equiv of tributylphosphine in the reaction mixture or by using allyl acetate as the substrate. Cyano ate complex, lithium cis-(eta1-allyl)cyanodimethylcuprate(III) was obtained in high yield by injecting allyl chloride or allyl acetate into the cyano-Gilman reagent, Me2CuLi.LiCN (B), in THF-d8 at -100 degrees C. Reactions of A with allylic substrates show a definite dependence on leaving group (chloride vs acetate), whereas those of B do not. Moreover, these reagents have different regioselectivities, which in the case of A vary with temperature. Finally, the exclusive formation of cis-cyano sigma-allyl CuIII intermediates in both the 1,4-addition of B to alpha-enones and its SN2alpha reaction with allylic substrates now makes sense in terms of pi-allyl intermediates in both cases, thus unifying the mechanisms of these two kinds of conjugate addition.

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Iodo-Gilman reagents Me 2 -CuLi´LiI, Bu 2 CuLi´LiI, and BuThCuLi´LiI and cyano-Gilman reagents (ne  e ªhigher order cyanocupratesº Me 2 CuLi´LiCN, Bu 2 CuLi´LiCN, and BuThCuLi´LiCN react with 2-cyclohexenone at various rates, which depend upon the R groups (Me, Bu, Th thienyl), Li salt (LiI vs. LiCN), solvent (ether vs. THF), and amount of trimethylsilyl chloride (TMSCl) additive. The effect of the Li salt (CuI vs. CuCN precursor) is less than that of solvent or TMSCl. The butylcuprate-iodocyclohexane reaction has also been examined as a function of Li salt, solvent, and TMSCl additive, and similar effects are observed. The reactivity matrix R with elements r i,j is a convenient way to store and present a large amount of relative reactivity data. Entry r i,j is the ratio of the rate with reagent i to the rate with reagent j, which we approximate by using yields measured after a short time (4 s). The logarithmic reactivity profile (LRP) provides an efficient means for determining yields under conditions where such comparisons are valid. The results of a large number of 4-point LRPs and related reactions are tabulated and analyzed to provide a clearer picture of organocuprate reactivity.