Heterobimetallic dibenzoindenyl (Cr(CO)3-Re(CO)3) complexes via chromium-templated [3 + 2 + 1]benzannulation: synthesis and molecular structures.

Heterobimetallic (di)benzoindenyl Re-Cr complexes have been prepared by a sequence starting from (8-bromobenzo[e]-indenyl)potassium. Reaction with pentacarbonylrhenium bromide affords tricarbonylrhenium complex 2, which has been modified to rhenium-chromium carbene complex 3. Its chromium-templated [3 + 2 + 1]benzannulation afforded the anti(Cr(CO)(3)-Re(CO)(3)) dibenzoindenyl complex 4 as the major product along with the syn diastereoisomer 5. The molecular structures of all heterobimetallic complexes were established by X-ray analyses.

Planar chiral (η5-cyclohexadienyl)- and (η6-arene)-tricarbonylmanganese complexes: synthetic routes and application.

Planar chiral arenetricarbonylchromium complexes have been intensively investigated and they have been applied as valuable building blocks for asymmetric synthesis and as ligands for asymmetric catalysis. In contrast, in the field of the isoelectronic cationic [(η(6)-arene)Mn(CO)(3)](+) complexes, until these last 10 years, very few studies were published involving nonracemic planar chiral cationic complexes and their potential applications, certainly because of the difficult access to enantiopure starting material. In 2009, however, the discovery of the first resolution of such compounds opened a new area for their application in the field of organic as well as of organometallic enantioselective syntheses. We felt it important to write a review on this subject to give an up-to-date summary of the methodologies used to prepare enantiomerically pure planar chiral neutral [(η(5)-cyclohexadienyl)Mn(CO)(3)] and cationic [(η(6)-arene)Mn(CO)(3)](+) complexes as well as their potential in enantioselective synthesis.

New access to (η(5)-cyclohexadienyl)Mn(CO)3 and cationic (η(6)-arene)Mn(CO)3 complexes by Suzuki-Miyaura reaction.

First Suzuki-Miyaura coupling reactions applied to (η(5)-chloro-cyclohexadienyl)Mn(CO)3 complexes are described and lead to the syntheses of (η(5)-aryl-cyclohexadienyl)Mn(CO)3 and of cationic (η(6)-arene)Mn(CO)3 complexes after rearomatization. The structures of two of the new complexes have been investigated by X-ray diffraction study.

Resolution of planar chiral cationic (eta6-arene)tricarbonylmanganese complexes.

This contribution describes the first resolution of cationic (eta(6)-arene)Mn(CO)(3) complexes through addition of d-(+)-camphor enolate, isomerization of the stereogenic center, and separation and recrystallization of the corresponding eta(5) diastereoisomers followed by rearomatization and elimination of the chiral auxiliary. This general unprecedented chiral nucleophile addition/elimination (eta(6)-eta(5))/(eta(5)-eta(6)) "round trip" sequence uses a cheap, commercially available chiral nucleophile. As it is compatible with the presence of halide and alkoxy groups, a huge number of applications are envisaged. Some of them, such as the synthesis of enantiopure substituted cyclohexenones, are reported in the present work.

First example of an enantiopure planar chiral ligand built on a (eta5-cyclohexadienyl)Mn(CO)3 scaffold.

The synthesis of (eta5-cyclohexadienyl)Mn(CO)3-based planar chiral ligands is realized by an efficient lithiation/electrophilic quench procedure, and the coordinating properties of one of them are highlighted together with its optical resolution.

Synthesis, characterization, and PGSE (1H and 19F) NMR diffusion studies on cationic (eta6- arene)Mn(CO)3+ complexes: boron counterion, ion pairing, and solvent dependences.

The synthesis, characterization, and PGSE ((1)H and (19)F) NMR diffusion studies on the cationic [(eta(6)-arene)Mn(CO)(3)][X] (arene = anisole, 4-chloroanisole, and 1,3,5-trimethoxybenzene; X = BPh(4) and BArF) are reported. The tetraphenyl borate complexes of anisole and 4-chloroanisole show surprisingly strong ion pairing in dichloromethane solution, whereas the BArF salts do not. (1)H,(1)H-NOESY data support this anion selectivity. In chloroform solution one finds the usual strong ion pairing for both anions. The solid-state structure of [(eta(6)-1,3,5-trimethoxybenzene)Mn(CO)(3)][BPh(4)] has been determined. (13)C NMR and IR data for the new complexes are reported. The observed IR frequencies are higher for the BArF complexes than for the BPh(4) complexes.

First asymmetric SmI2-induced cross-coupling of Cr(CO)3 aromatic nitrone complexes with carbonyl compounds.

The SmI(2)-induced cross-coupling of Cr(CO)(3)-complexed nitrones with carbonyl compounds is described. This highly chemo- and diastereoselective reaction affords enantiopure [small beta]-amino alcohol complexes in excellent yields.