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.

A series of Werner complexes featuring the tridentate ligand smif, that is, 1,3-di-(2-pyridyl)-2-azaallyl, have been prepared. Syntheses of (smif)(2)M (1-M; M = Cr, Fe) were accomplished via treatment of M(NSiMe(3))(2)(THF)(n) (M = Cr, n = 2; Fe, n = 1) with 2 equiv of (smif)H (1,3-di-(2-pyridyl)-2-azapropene); ortho-methylated ((o)Mesmif)(2)Fe (2-Fe) and ((o)Me(2)smif)(2)Fe (3-Fe) were similarly prepared. Metatheses of MX(2) variants with 2 equiv of Li(smif) or Na(smif) generated 1-M (M = Cr, Mn, Fe, Co, Ni, Zn, Ru). Metathesis of VCl(3)(THF)(3) with 2 Li(smif) with a reducing equiv of Na/Hg present afforded 1-V, while 2 Na(smif) and IrCl(3)(THF)(3) in the presence of NaBPh(4) gave [(smif)(2)Ir]BPh(4) (1(+)-Ir). Electrochemical experiments led to the oxidation of 1-M (M = Cr, Mn, Co) by AgOTf to produce [(smif)(2)M]OTf (1(+)-M), and treatment of Rh(2)(O(2)CCF(3))(4) with 4 equiv Na(smif) and 2 AgOTf gave 1(+)-Rh. Characterizations by NMR, EPR, and UV-vis spectroscopies, SQUID magnetometry, X-ray crystallography, and DFT calculations are presented. Intraligand (IL) transitions derived from promotion of electrons from the unique CNC(nb) (nonbonding) orbitals of the smif backbone to ligand π*-type orbitals are intense (ε ≈ 10,000-60,000 M(-1)cm(-1)), dominate the UV-visible spectra, and give crystals a metallic-looking appearance. High energy K-edge spectroscopy was used to show that the smif in 1-Cr is redox noninnocent, and its electron configuration is best described as (smif(-))(smif(2-))Cr(III); an unusual S = 1 EPR spectrum (X-band) was obtained for 1-Cr.

Lithium tetramethylcuprate(III), Me(4)CuLi, the Cu(III) analog of the Gilman reagent, has been prepared in high yield from halo-Gilman reagents Me(2)CuLi.LiX (X = Cl, Br, I) and 2,3-dichloropropene and found to have surprising thermal stability. The cyano-Gilman reagent (X = CN) follows a different pathway.

Aryl-oxazoline synthons have been explored for the preparation of strong-field first-row transition metal chelate species. With 4,4-dimethyl-2-phenyloxazoline (HPhOx), no CH bond activations afforded complexation, and aside from Zn(κ-C,N-4,4-Me 2 -2-(o-C 6 H 4 )oxazoline) 2 (Zn(PhOx) 2 ), aryl-coupling reactions were noted with 4,4-dimethyl-2-(2-lithiophenyl)oxazoline (LiPhOx) and MX 2 ; [κ-N,N-{4,4-Me 2 -(2-o-C 6 H 4 )-2-oxazoline} 2 ]CoCl 2 (1-Co) was structurally characterized. Metalations with 4,4-dimethyl-2-benzyloxazoline (PhCH 2 Ox) were prone to deprotonation, as exemplified by (Me 2 62 ), and iron, i.e., {κ-C,N-{(o-C 6 H 4 )CMe 2 (COCH 2 CMe 2 N)}Fe(py)Cl ( 7) products. Bis-aryloxazoline metal complexes proved difficult to prepare, with {κ-C,N-(o-C 6 H 4 )-CMe 2 (COCH 2 CMe 2 N)} 2 M (M=Ni, 9) the only clear example, although NMR evidence exists for M=Fe (8). ‡ Dedicated to Dietmar Seyferth on the occasion of his retirement as Editor, for his distinguished service, and for 35þ years of friendship to an old student.