Center for Magnetic Resonance

E.A. Valishina, M.F.C. Guedes da Silva, M.A. Kinzhalov, S.A. Timofeeva, T.M. Buslaeva, M. Haukka, A.J.L. Pombeiro, V.P. Boyarskiy, V.Yu. Kukushkin, K.V. Luzyanin

“Palladium-ADC complexes as efficient catalysts in copper-free and room temperature Sonogashira coupling”

J. Molec. Catalysis , 2014, 395, 162-171

DOI:10.1016/j.molcata.2014.08.018

The metal-mediated coupling between cis-[PdCl₂(CNR¹)₂] [R¹ = cyclohexyl (Cy) 1, t-Bu 2, 2,6-Me₂C₆H₃ (Xyl) 3, 2-Cl-6-MeC₆H₃ 4] and hydrazones H₂NN=CR²R³ [R², R³ = Ph 5; R², R³ = C₆H₄(OMe-4) 6; R²/R³ = 9-fluorenyl 7; R² = H, R³ = C6H4(OH-2) 8] provided carbene complexes cis-[PdCl₂{C(N(H)N=CR²R³)=N(H)R¹}(CNR¹)] (9–24) in good (80–85%) yields. Complexes 9–24 showed high activity [yields up to 99%, and turnover numbers (TONs) up to 3.7 × 10⁴] in the Sonogashira coupling of various aryl iodides with a range of substituted aromatic alkynes without the need of copper co-catalyst. The catalytic procedure runs at 80 °C for 1 h in EtOH using K₂CO₃ as a base. No formation of homocoupling or acetylene decomposition products was observed. Designed copper-free Sonogashira system can also run at room temperature giving target products with yields up to 87% and TONs up to 87.

I.I. Eliseev, P.V. Gushchin, Yi.-A. Chen, P.-T. Chou, M. Haukka, G.L. Starova, V.Yu. Kukushkin

“Phosphorescent Pt(II) Systems Featuring Both 2,2’-Dipyridylamine and 1,3,5-Triazapentadiene Ligands”

Eur. J. Inorg. Chem. 2014 , 4101-4108

DOI:10.1002/ejic.201402364

The treatment of cis-[Pt(dpa)(RCN)₂][SO₃CF₃]₂ {dpa = 2,2′-dipyridylamine, R = Me, Et, CH₂Ph, Ph; [2a–d](OTf)₂} (OTf = SO₃CF₃) with 2 equiv. of N,N′-diphenylguanidine [NH=C(NHPh)₂] in CH₂Cl₂ solutions at room temp. for 16 h gives [Pt(dpa){NH=C(R)NC(NHPh)=NPh}][SO₃CF₃] {[3a,b,d](OTf)} as the addition products and [Pt(dpa){NH=C(R)NHC(R)=NH}][SO₃CF₃]₂ {[4a,b](OTf)₂} as the tailoring products. The formulation of complexes [3a,b,d](OTf) and [4a,b](OTf)₂ was supported by satisfactory C, H, and N elemental analyses and agreeable high-resolution ESI-MS, IR, and ¹H (including ¹H–¹H COSY experiments) and ¹³C{¹H} NMR data. The structures of all of the platinum species were determined by single-crystal X-ray diffraction. The resultant complexes are nonemissive in solution, mainly because of the interaction between the empty d_z² orbital in a square-planar configuration and solvent molecules. However, in the solid state, complexes [3a,b,d](OTf) exhibit strong phosphorescence with quantum yields (peak wavelength) of 0.23 (490 nm), 0.27 (483 nm), and 0.20 (532 nm), respectively.

O.Yu. Bakulina, A.Yu. Ivanov, D.V. Dar’in, P.S. Lobanov

“New transformations of 2-methylsulfanyl-4,6-dichloropyrimidine-5-carbaldehyde involving enamines: synthesis of condensed azines”

Mendeleev Commun 2014, 24, 163-164

DOI: 10.1016/j.mencom.2014.04.013

The reaction between 4,6-dichloropyrimidine-5-carbaldehyde and methyl 3-aminocrotonate leads to pyrido[2,3-d]pyrimidine which reacts with ethyl 3,3-diaminoacrylate to give pyrimido[4,5,6-de][1,6]naphthyridine derivative. The structure of the latter was confirmed by XRD analysis.

D.S. Ryabukhin, L.Yu. Gurskaya, G.K. Fukin, A.V. Vasilyev

“Superelectrophilic activation of N-aryl amides of 3-arylpropynoic acids: synthesis of quinolin-2(1H)-one derivatives”

Tetrahedron Lett., 2014, 70, 6428-6443

DOI: 0.1016/j.tet.2014.07.028

The superelectrophilic activation of N-aryl amides of 3-arylpropynoic acids by Bronsted superacids (CF3SO3H, HSO3F) or strong Lewis acids AlX3 (XјCl, Br) results in the formation of 4-aryl quinolin-2(1H)-ones in quantitative yields. The vinyl triflates or vinyl chlorides may be formed as additional reaction products. The investigated amides in reactions with benzene give 4,4-diaryl 3,4-dihydroquinolin-2-(1H)-ones under the superelectrophilic activation. 4-Aryl quinolin-2(1H)-ones in POCl3 are converted into 4-aryl 2-chloroquinolines. 4-Fluorophenyl-4-phenyl 3,4-dihydroquinolin-2-(1H)-one give N-formylation products in a yield of 79% under the VilsmeiereHaack reaction conditions.

A.V. Stepakov, V.M. Boitsov, A.G. Larina, A.P. Molchanov

”Acid-induced rearrangement of cycloadducts from N-aryl itaconimides and 1,3-diphenylisobenzofuran”

Tetrahedron Lett., 2014, accepted

DOI: 10.1016/j.tetlet.2014.06.107

Treatment of several Diels–Alder adducts of N-aryl itaconimides and 1,3-diphenylisobenzofuran with a strong acid triggers a skeletal rearrangement resulting in 2-aryl-6,10b-diphenylbenzo[h]isoquinoline-1,3(2H,10bH)-diones.

V.A. Rassadin, E. Nicolas, Y. Six

“Ti(OiPr)₄/nBuLi: an attractive reagent system for [2+2+2] cyclotrimerisation reactions”

Chem. Commun. 2014, Advance Article

DOI: 10.1039/C4CC02698E

A convenient method for the [2+2+2] cyclotrimerisation of alkynes using Ti(OiPr)₄/nBuLi is presented. Homotrimerisation of arylacetylenes proceeds within minutes with excellent regioselectivity. Moreover, the intermolecular construction of ABB heterotrimers can be achieved selectively from two different alkynes with similar electronic properties. The method is also suitable for the synthesis of pyridines.