992-04-1Relevant articles and documents
Synthesis and fluorescence of 3,4,6,7,8,9-hexaphenyl-1H-benzo[g]isochromen-1-one
Loginov, Dmitry A.,Molotkov, Alexander P.,Shepel', Nikolay E.
, p. 67 - 70 (2018)
Highly step- and atom-economic synthetic route to 3,4,6,7,8,9-hexaphenyl-1H-benzo[g]isochromen-1-one (1) based on the rhodium catalyzed reaction of terephthalic acid with diphenylacetylene was developed. The best catalytic system for this reaction is [CpRhI2]n/Cu(OAc)2. Compound 1 shows fluorescent properties with a strong Stokes shift.
Quasilinear 3d-metal(i) complexes [KM(N(Dipp)SiR3)2] (M = Cr-Co) - structural diversity, solution state behaviour and reactivity
Bontemps, Sébastien,Duhayon, Carine,Müller, Igor,Sabo-Etienne, Sylviane,Weller, Ruth,Werncke, C. Gunnar
, p. 4890 - 4903 (2021)
The synthesis and characterization of neutral quasilinear 3d-metal(i) complexes of chromium to cobalt of the type [KM(N(Dipp)SiMe3)2] (Dipp = 2,6-di-iso-propylphenyl) are reported. In solid state these metal(i) complexes either occur as isolated molecules (Co) or are part of a potassium ion linked 1D-coordination polymer (Cr-Fe). In solution the potassium cation is either ligated within the ligand sphere of the metal silylamide or is separated from the complex depending on the solvent. For iron, we showcase that it is possible to use sodium or lithium metal for the reduction of the metal(ii) precursor. However, in these cases the resulting iron(i) complexes can only be isolated upon cation separation using an appropriate crown-ether. Further, the neutral metal(i) complexes are used to introduce NBu4+as an organic cation in the case of cobalt and iron. The impact of the intramolecular cation complexation was further demonstrated upon reaction with diphenyl acetylene which leads to bond formation processes and redox disproportionation instead of η2-alkyne complex formation.
Deactivation of the cobalt catalyst for the cyclotrimerization of acetylenes in ionic liquids: Solvent effects on the mechanism and thermal and pressure activation parameters
Aviles, Teresa,Jansat, Susanna,Martinez, Manuel,Montilla, Francisco,Rodriguez, Carlos
, p. 3919 - 3922 (2011)
The deactivation reaction of the [CoCp(1,4-σ-C4[Ph] 4)PPh3] catalyst for the cyclotrimerization of acetylenes has been kinetico-mechanistically studied under different temperature, pressure, and solvent conditions. The results indicate a dramatic change in mechanism from conventional to ionic liquid solvents due to the polarity of the medium.
Case Study of N-iPr versus N-Mes Substituted NHC Ligands in Nickel Chemistry: The Coordination and Cyclotrimerization of Alkynes at [Ni(NHC)2]
Tendera, Lukas,Helm, Moritz,Krahfuss, Mirjam J.,Kuntze-Fechner, Maximilian W.,Radius, Udo
supporting information, p. 17849 - 17861 (2021/11/17)
A case study on the effect of the employment of two different NHC ligands in complexes [Ni(NHC)2] (NHC=iPr2ImMe 1Me, Mes2Im 2) and their behavior towards alkynes is reported. The reaction of a mixture of [Ni2(iPr2ImMe)4(μ-(η2 : η2)-COD)] B/ [Ni(iPr2ImMe)2(η4-COD)] B’ or [Ni(Mes2Im)2] 2, respectively, with alkynes afforded complexes [Ni(NHC)2(η2-alkyne)] (NHC=iPr2ImMe: alkyne=MeC≡CMe 3, H7C3C≡CC3H7 4, PhC≡CPh 5, MeOOCC≡CCOOMe 6, Me3SiC≡CSiMe3 7, PhC≡CMe 8, HC≡CC3H7 9, HC≡CPh 10, HC≡C(p-Tol) 11, HC≡C(4-tBu-C6H4) 12, HC≡CCOOMe 13; NHC=Mes2Im: alkyne=MeC≡CMe 14, MeOOCC≡CCOOMe 15, PhC≡CMe 16, HC≡C(4-tBu-C6H4) 17, HC≡CCOOMe 18). Unusual rearrangement products 11 a and 12 a were identified for the complexes of the terminal alkynes HC≡C(p-Tol) and HC≡C(4-tBu-C6H4), 11 and 12, which were formed by addition of a C?H bond of one of the NHC N-iPr methyl groups to the C≡C triple bond of the coordinated alkyne. Complex 2 catalyzes the cyclotrimerization of 2-butyne, 4-octyne, diphenylacetylene, dimethyl acetylendicarboxylate, 1-pentyne, phenylacetylene and methyl propiolate at ambient conditions, whereas 1Me is not a good catalyst. The reaction of 2 with 2-butyne was monitored in some detail, which led to a mechanistic proposal for the cyclotrimerization at [Ni(NHC)2]. DFT calculations reveal that the differences between 1Me and 2 for alkyne cyclotrimerization lie in the energy profile of the initiation steps, which is very shallow for 2, and each step is associated with only a moderate energy change. The higher stability of 3 compared to 14 is attributed to a better electron transfer from the NHC to the metal to the alkyne ligand for the N-alkyl substituted NHC, to enhanced Ni-alkyne backbonding due to a smaller CNHC?Ni?CNHC bite angle, and to less steric repulsion of the smaller NHC iPr2ImMe.
Exploration of [2 + 2 + 2] cyclotrimerisation methodology to prepare tetrahydroisoquinoline-based compounds with potential aldo-keto reductase 1C3 target affinity
Santos, Ana R. N.,Sheldrake, Helen M.,Ibrahim, Ali I. M.,Danta, Chhanda Charan,Bonanni, Davide,Daga, Martina,Oliaro-Bosso, Simonetta,Boschi, Donatella,Lolli, Marco L.,Pors, Klaus
supporting information, p. 1476 - 1480 (2019/08/20)
Tetrahydroisoquinoline (THIQ) is a key structural component in many biologically active molecules including natural products and synthetic pharmaceuticals. Here, we report on the use of transition-metal mediated [2 + 2 + 2] cyclotrimerisation of alkynes to generate tricyclic THIQs with potential to selectively inhibit AKR1C3.
