Catalytic alkylation of methyl-N-heteroaromatics with alcohols.

A novel catalytic C-C coupling reaction in which N-heteroaromatic-substituted methyl groups are efficiently alkylated using primary alcohols is introduced. The synthesis protocol is based on iridium catalysts and most likely relies on the "borrowing hydrogen" or "hydrogen autotransfer" mechanism. A variety of substrate combinations can readily be employed in this reaction, including pyrimidines, pyrazines, pyridazines, and even fairly activated 2- and 4-picolines.

Selective iridium-catalyzed alkylation of (hetero)aromatic amines and diamines with alcohols under mild reaction conditions.

A P,N-ligand-coordinated iridium complex has been employed as an efficient catalyst for the selective monoalkylation of (hetero)aromatic amines with alcohols. A significant improvement of this alkylation method has been achieved, such that it can be performed at a temperature of 70 degrees C and with catalyst loadings as low as 0.1 mol % Ir, while still affording excellent yields of secondary amines. Furthermore, the high selectivity of this catalyst for the monoalkylation of aromatic amino functions has been successfully exploited for the alkylation of diamines in both symmetric and nonsymmetric fashions, providing a novel and very efficient synthetic tool for the preparation of N,N'-dialkylated aromatic diamines.

Iron-catalyzed aryl-aryl cross-coupling reaction tolerating amides and unprotected quinolinones.

The iron(III)-catalyzed cross-coupling reaction between functionalized arylcopper reagents and aromatic iodides bearing an amide function or an unprotected quinolinone leads smoothly to polyfunctionalized biphenyls in excellent yields due to an intramolecular chelating effect of the amide group.

Single and double C-Cl-activation of methylene chloride by P,N-ligand coordinated rhodium complexes.

Two in one: The simultaneous formation of bimetallic mu-methylene bridged Rh(III) complexes as well as dimeric Rh(III) complexes with terminal chloromethyl groups is observed for P,N-ligand stabilized Rh(I) complexes by C-Cl bond activation of methylene chloride. A mechanistic proposal for the formation of both activation products is also discussed. The synthesis of Rh(I) complexes with P-functionalized aminopyridine ligands is reported as well as the first simultaneous observation of a single and double activation of C-Cl bonds of methylene chloride affording both a dimeric Rh(III) complex bearing terminal CH(2)Cl groups in addition to a binuclear Rh(III) complex with a bridging mu-CH(2) group. The structures of the oxidative addition products were obtained by X-ray diffraction studies and NMR experiments were performed to elucidate some aspects of the reaction pathway.

Aminoborylene complexes of group 6 elements and iron: a synthetic, structural, and quantum chemical study.

Transition-metal-borylene complexes of the type [(OC)(5)M=BR] {M=Cr, Mo, W; R=N(SiMe(3))(2), 1a-3a, Si(SiMe(3))(3), 4a} and [(OC)(4)Fe=B=N(SiMe(3))(2)] (8) were prepared by salt elimination reactions. Synthesis of the latter complex was accompanied by the formation of substantial amounts of an unusual dinuclear iron complex [Fe(2){mu-C(2)O(2)(BN(SiMe(3))(2))}(2)(CO)(6)] (9). The aminoborylene complexes of Group 6 metals were converted to trans-[(Cy(3)P)(CO)(4)M=B=N(SiMe(3))(2)] (5a-7a) by irradiation in the presence of PCy(3). Structural and spectroscopic parameters were discussed with respect to the trans-effect of the borylene ligand and the degree of M-B d(pi)-p(pi)-backbonding. Computational studies were performed on Group 6-borylene complexes. The population and topological analyses as well as the molecular orbital composition are consistent with the presence of both sigma-and pi-type interactions. There are, however, indications that the d(pi)-p(pi)-backbonding in the silylborylene complex is significantly more pronounced than in the aminoborylene complexes.