41898-97-9

Upstream product

• 857982-87-7 1-(2,5-dipropyl-phenyl)-propan-1-one 
• 627-19-0 1-Pentyne 
• 4815-57-0 1,4-di(n-propyl)benzene 

Downstream Products

• 17171-72-1 1,3-dipropyl-benzene 
• 15181-14-3 1,3,5-tri(1-propyl)benzene 

Relevant academic research and scientific papers

H-BPin/KOtBu Promoted Activation of Cobalt Salt to a Heterotopic Catalyst for Highly Selective Cyclotrimerization of Alkynes

A mixture of HBPin with KOtBu was found to activate cobalt salt to form a heterotopic cobalt species that is highly active for catalytic intermolecular trimerization of alkynes. This protocol affords 1,2,4-regioisomers in good yields with high regioselectivities under mild conditions. These salient features, together with the operational simplicity and high efficiency, as well as obviating the use of any costly and/or air sensitive ligands, renders the protocol promising for practical applications.

Case Study of N-iPr versus N-Mes Substituted NHC Ligands in Nickel Chemistry: The Coordination and Cyclotrimerization of Alkynes at [Ni(NHC)2]

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.

Catalytic activity of a large Rhodium metallaborane towards the [2+2+2] cycloaddition of alkynes

Rhodadecaborane [6-(η5-C5Me5)-nido-6-RhB9H13] (1) was found to be able to catalyze the [2+2+2] cycloaddition of a series of terminal and internal alkynes to yield mixtures of 1,2,4- and 1,3,5-substituted benzene. The reactivity of compound 1 with alkynes demonstrates that decaborane based metallaborane can be used as the catalyst for [2+2+2] cycloaddition of alkynes. All compounds are characterized by NMR spectroscopy and MS spectrometry methods.

Highly regioselective [2+2+2] cycloaddition of terminal alkynes catalyzed by titanium complexes of p-tert-butylthiacalix[4]arene

Mono- and dinuclear titanium complexes of p-tert-butylthiacalix[4]arene were applied as a catalyst for [2+2+2] cycloaddition of terminal alkynes. They showed high catalytic activity and regioselectivity toward 1,3,5-trisubstituted benzenes over 1,2,4-trisubstituted isomers. The regioselectivity was rationalized in terms of the steric effect of the thiacalixarene skeleton and the coordination of the bridging sulfur atom to the titanium center.

Highly regioselective [2 + 2 + 2] cycloaddition of terminal alkynes catalyzed by η6-arene complexes of titanium supported by dimethylsilyl-bridged p-tert-butyl calix[4]arene ligand

Two new Ti-η6-arene complexes [(DMSC)Ti{η6-1,2,4-C6H3(SiMe 3)3}] (6) and [(DMSC)Ti{η6-1,3,5-C6H3But 3}] (7) containing 1,2-alternate, Me2Si-bridged p-tert-butylcalix[4]arene (DMSC) ancillary ligand have been synthesized. The solid-state structure of 6 revealed a highly folded arene ligand [with a dihedral angle of 29.7(7)○] and suggests that 6 is better described as a 7-titananorbornadiene species. Both 6 and 7 are efficient catalysts for highly regioselective [2 + 2 + 2] cycloaddition of terminal alkynes to yield 1,2,4-substituted benzenes. Kinetic studies of the catalytic [2 + 2 + 2] cycloaddition of Me3SiC≡CH revealed first-order dependence on [6] and [Me3SiC≡CH]; and activation parameters, ΔH? = 14 kcal/mol, and ΔS? = - 11 cal/mol K, that are consistent with an associative mechanism. The reaction rate is influenced by the steric requirements of both the alkyne and the η6-arene compound. The high selectivity for 1,2,4-substituted benzene may be understood in terms of the directing influence of the DMSC ligand.

Cyclotrimerization of Alkynes using as Activated Zirconium-Titanium Catalyst Prepared by the Reduction of Zirconium Tetrachloride and Titanium Trichloride with Lithium Powder

Activated zirconium-titanium prepared by the reduction of zirconium tetrachloride and titanium trichloride with lithium efficiently catalyses the cyclotrimerization of alkynes.