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Abstract: The asymmetric intramolecular Mizoroki–Heck reaction of prochiral tricarbonyl(2,6-dibutenylchlorobenzene)chromium in the presence of a chiral phosphine–palladium catalyst gave the corresponding bicyclic chromium complex up to 73% ee. [Copyright &y& Elsevier]

Various substrates are applied for the facile ring-closing metathesis in the coordination sphere of (η5-cyclopentadienyl)manganese complexes leading to C3- or C4-bridged manganese complexes. [ABSTRACT FROM AUTHOR]

Abstract: A new dinuclear ruthenium(II) catecholato complex [Cp*Ru(κ2:η6-μ2-1,2-O2C6H4)RuCp*] (3; Cp*=η5-C5Me5) has been prepared by the reaction of [Cp*RuCl]4 with 2 equiv. of disodium catecholate in THF. Complex 3 has a dinuclear structure, in which one of the Cp*Ru fragments is κ2-bonded to the two oxygen atoms and the other is η6-bonded to the aromatic ring. Similar treatment of [Cp*RuCl]4 with disodium 2,3-naphthalenediolate affords an analogous κ2:η6-bonded dinuclear complex [Cp*Ru(κ2:η6-μ2-2,3-O2C10H6)RuCp*] (4) with selective π-complexation at the oxygen-substituted naphthalene ring. The molecular structure of 4 has been determined by X-ray crystallography. The oxygen-bound ruthenium atoms in complexes 3 and 4 are coordinatively unsaturated and readily uptake 1 equiv. of carbon monoxide to give the corresponding carbonyl adducts [Cp*Ru(CO)(κ2:η6-μ2-1,2-O2C6H4)RuCp*] (5) and [Cp*Ru(CO)(κ2:η6-μ2-2,3-O2C10H6)RuCp*] (6), respectively. [Copyright &y& Elsevier]

Abstract: A variety of phosphine-chelate (π-arene)chromium complexes were prepared in good to excellent yields by the ring-closing metathesis reaction of [η6-(ω-alkenyl)benzene][(ω-alkenyl)phosphine]chromium(0) dicarbonyl complexes catalyzed by the Grubbs’ ruthenium–carbene complexes. [Copyright &y& Elsevier]

A diphosphene ligand possessing a PP bond and a phosphineborane moiety in its molecule was synthesized. The reaction of the new bidentate diphosphene-phosphineborane ligand with [Rh(cod) 2 ]BF 4 provided a cationic diphosphene-rhodium complex with cis -coordination through the η 1 -PP and η 2 -BH 3 moieties. The complex was applied to the coupling reaction of benzimidazole with cyclohexylallene. The complex also underwent a ligand exchange reaction with N-donor reagents such as N -methylpyrrolidine and N , N , N , N -tetramethylethylenediamine. In particular, the addition reaction of pyridine with the rhodium complex provided an equilibrium mixture of the rhodium complex, pyridine, the diphosphene-phosphineborane ligand, and [Rh(pyridine) 2 (cod)]BF 4 .

Although arynes are usually considered fleeting intermediates, they are highly valuable synthons because they enable the introduction of aromatic rings and the simultaneous formation of new bonds at two sites. Although catalytic reactions using transition metals are excellent method for constructing complex polycyclic aromatic molecules in a single step, the use of asymmetric catalysis for the capture of arynes remains a crucial goal for the progress of aryne chemistry. Catalytic asymmetric reactions of arenes are challenging, requiring sufficient interactions between the neutral and highly reactive short-lived aryne intermediates in a stereo-controlled fashion. In addition, spontaneous decomposition, as well as side reactions, has hindered their development and, until recently, highly enantioselective reactions using arynes had remained elusive. This Review highlights asymmetric reactions using arynes, featuring diastereoselective, enantioselective and catalytic enantioselective reactions., (© 2023. Springer Nature Limited.)

Catalytic enantioselective 1,2-addition reactions of arylboronic acids with 1,2,5-thiadiazoline 1,1-dioxide derivatives were achieved using planar-chiral phosphine-olefin ligand L5 with a bis[(2,3,4,5,6-pentafluoro)phenyl]phosphino group, showing ≤98% ee. The enantioselectivities of the addition products were improved by increasing the number of fluoro substituents on the aromatic ring of the ligand. X-ray crystallographic studies of 3aa and [RhCl/ L5 ] 2 revealed the absolute configuration of the enantioenriched addition product 3 and the mode of phosphine-olefin bidentate coordination of L5 to a rhodium(I) cation.

Dibenzo[b,g]phosphindolizine oxide and three types of benzo[e]naphthophosphindolizine oxides have been synthesized by the ring-closing metathesis of benzo[b]phosphole oxide and naphthophosphole oxides with two olefin tethers. Their molecular structures and properties were revealed by X-ray crystallographic analysis, UV-vis spectroscopy, and electrochemical analysis. The number and position of the benzene rings were found to alter the structural geometry and the HOMO/LUMO energy levels, and their effects were investigated by theoretical calculations. Among the phosphindolizine oxide derivatives investigated, only benzo[e]naphtho[2,3-b]phosphindolizine oxide with the naphthalene ring fused at 2,3-positions showed weak yellow fluorescence with a large Stokes shift., (© 2022 Wiley-VCH GmbH.)

Organophosphorus compounds possessing a P-P double-bond character are intriguing materials in coordination chemistry because it is possible to form a variety of coordination modes from the π-bond in addition to the lone pairs. We report herein the complexation of a new bidentate ligand, ethylene-tethered bis(binaphthyldiphosphene) ( S , S )-2, with palladium(II) species. The reaction of ( S , S )-2 with [Pd(π-allyl)(cod)](SbF 6 ) and PdCl 2 (cod) afforded η 1 /η 1 -bis(diphosphene) complex 7 and η 1 -diphosphene/η 2 -phosphanylphosphide complex 8, respectively. The latter was characterized by a chloride migration from the palladium atom to a phosphorus atom due to the high electron-accepting character of the PP moiety. Theoretical calculations revealed the migration process and nature of complex 8.

Transformation of triple helicene (TH) to double helicene (DH) with adjacent stereogenic carbon atoms and axial stereogenicity was achieved by the unexpected conjugate addition to the central aromatic ring of TH-1. We also studied the boundary at which different reactivities to addition reactions occur in some helicenes with different π-extension.

Invited for the cover of this issue is Ken Kamikawa and co-workers at Osaka Prefecture University and RIKEN Center for Sustainable Resource Science. The image depicts an S-shaped double azahelicene capturing the palladium in a trans-chelating fashion. Read the full text of the article at 10.1002/chem.202002405., (© 2020 Wiley-VCH GmbH.)

The molybdenum-catalyzed asymmetric ring-closing metathesis of the various Cs -symmetric (π-arene)chromium substrates provides the corresponding bridged planar-chiral (π-arene)chromium complexes in excellent yields with up to >99 % ee. With a bulky and unsymmetrical substituent, such as N-indolyl or 1-naphthyl, at the 2-positions of the η(6) -1,3-diisopropenylbenzene ligands, both biaryl-based axial chirality and π-arene-based planar chirality are simultaneously induced in the products. The axial chirality is retained even after the removal of the dicarbonylchromium fragment, and the chiral biaryl/heterobiaryl compounds are obtained with complete retention of the enantiopurity., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

[reaction: see text] N-Aryl indoles with axially chiral N-C bonds were synthesized by stereoselective nucleophilic aromatic substitution reactions of planar chiral arene chromium complexes. Stereoselective chromium tricarbonyl migration was achieved in the sterically hindered N-aryl indole chromium complex by refluxing in toluene.