84941-01-5

Upstream product

• 627-41-8 propargyl alcohol methyl ether 
• 4464-18-0 1,3,5-tris(hydroxymethyl)benzene 
• 74-88-4 methyl iodide 

Downstream Products

• 862203-43-8 (+)-(R,R,R)-1,3,5-tris[1-methoxy-2-(3-pyridyl)ethyl]benzene 

Relevant academic research and scientific papers

Synthesis of a Strained Spherical Carbon Nanocage by Regioselective Alkyne Cyclotrimerization

The smallest spherical carbon nanocage so far, [2.2.2]carbon nanocage, has been synthesized by the cationic rhodium(I)/H8-binap complex-catalyzed regioselective intermolecular cyclotrimerization of a cis-1-ethynyl-4-arylcyclohexadiene derivative followed by the triple Suzuki–Miyaura cross-couplings with 1,3,5-triborylbenzene and reductive aromatization. This cage molecule is highly strained, and its ring strain is between those of [6] and [5]cycloparaphenylenes. A significant red-shift of an emission maximum was observed, compared with that of known [4.4.4]carbon nanocage. The sequential cyclotrimerizations of a cis-1,4-diethynylcyclohexadiene derivative with the same rhodium(I) catalyst followed by reductive aromatization failed to afford [1.1.1]carbon nanocage; instead, a β-graph-shaped cage molecule was generated.

Enhanced Catalytic Activity of Nickel Complexes of an Adaptive Diphosphine-Benzophenone Ligand in Alkyne Cyclotrimerization

Adaptive ligands, which can adapt their coordination mode to the electronic structure of various catalytic intermediates, offer the potential to develop improved homogeneous catalysts in terms of activity and selectivity. 2,2′-Diphosphinobenzophenones have previously been shown to act as adaptive ligands, the central ketone moiety preferentially coordinating reduced metal centers. Herein, the utility of this scaffold in nickel-catalyzed alkyne cyclotrimerization is investigated. The complex [(p-tolL1)Ni(BPI)] (p-tolL1 = 2,2′-bis(di(para-tolyl)phosphino)-benzophenone; BPI = benzophenone imine) is an active catalyst in the [2 + 2 + 2] cyclotrimerization of terminal alkynes, selectively affording 1,2,4-substituted benzenes from terminal alkynes. In particular, this catalyst outperforms closely related bi- and tridentate phosphine-based Ni catalysts. This suggests a reaction pathway involving a hemilabile interaction of the C-O unit with the nickel center. This is further borne out by a comparative study of the observed resting states and DFT calculations.

METHOD FOR PRODUCING BENZENE COMPOUND AND CATALYST FOR PRODUCING BENZENE COMPOUND

PROBLEM TO BE SOLVED: To provide a method for producing a benzene compound capable of performing production of various benzene compounds with low environmental load without generating waste as in the case of using benzene as a starting raw material and to provide a catalyst used for the production method. SOLUTION: There are provided: a method for producing a benzene compound from alkynes in the presence of a catalyst, wherein the catalyst is a PdAu supported catalyst obtained by supporting Pd and Au in a molar ratio of 1:1 to 1:10 on a carrier; and a catalyst used for the production method. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT

Concerted Catalysis by Adjacent Palladium and Gold in Alloy Nanoparticles for the Versatile and Practical [2+2+2] Cycloaddition of Alkynes

A Pd-Au alloy efficiently catalyzed the [2+2+2] cycloaddition of substituted alkynes. Whereas monometallic Pd and Au catalysts were totally ineffective, Pd-Au alloy nanoparticle catalysts with a low Pd/Au molar ratio showed high activity to give the corresponding polysubstituted arenes in high yields. A variety of substituted alkynes participated in various modes of cycloaddition under Pd-Au alloy catalysis. The Pd-Au alloy catalysts exhibited high air tolerance and reusability.

Divergent reactivity of a new dinuclear xanthene-bridged bis(iminopyridine) di-nickel complex with alkynes

The reaction of a dinucleating bis(iminopyridine) ligand L bearing a xanthene linker (L = N,N′-(2,7-di-tert-butyl-9,9-dimethyl-9H-xanthene-4,5-diyl)bis(1-(pyridin-2-yl)methanimine)) with Ni2(COD)2(DPA) (COD = cyclooctadiene, DPA = diphenylacetylene) leads to the formation of a new dinuclear complex Ni2(L)(DPA). Ni2(L)(DPA) can also be obtained in a one-pot reaction involving Ni(COD)2, DPA and L. The X-ray structure of Ni2(L)(DPA) reveals two square-planar Ni centers bridged by a DPA ligand. DFT calculations suggest that this species features NiI centers antiferromagnetically coupled to each other and their iminopyridine ligand radicals. Treatment of Ni2(L)(DPA) with one equivalent of ethyl propiolate (HCCCO2Et) forms the Ni2(L)(HCCCO2Et) complex. Addition of the second equivalent of ethyl propiolate leads to the observation of cyclotrimerised products by 1H NMR spectroscopy. Carrying out the reaction under catalytic conditions (1 mol% of Ni2(L)(DPA), 24 h, room temperature) transforms 89% of the substrate, forming primarily benzene products (triethyl benzene-1,2,4-tricarboxylate and triethyl benzene-1,3,5-tricarboxylate) in 68% yield, in a ca. 5:1 relative ratio. Increasing catalyst loading to 5 mol% leads to the full conversion of ethyl propiolate to benzene products; no cyclotetramerisation products were observed. In contrast, the reaction is significantly more sluggish with methyl propargyl ether. Using 1 mol% of the catalyst, only 25% conversion of methyl propargyl ether was observed within 24 h at room temperature. Furthermore, methyl propargyl ether demonstrates the formation of cyclooctatetraenes in significant amounts at a low catalyst concentration, whereas a higher catalyst concentration (5 mol%) leads to benzene products exclusively. Density functional theory was used to provide insight into the reaction mechanism, including structures of putative dinuclear metallocyclopentadiene and metallocycloheptatriene intermediates.

Synthesis of ruthenium half-sandwich complexes by naphthalene replacement in [CpRu(C10H8)]+

Replacement of the naphthalene ligand in ruthenium complex [CpRu(C 10H8)]+ (1) by halide anions readily proceeds at room temperature to give insoluble oligomeric species [CpRuX]n (X = Cl, Br, I). Similar reactions in the presence of mono- or bidentate ligands afford complexes [CpRuL2X] where L = CO, P(OMe)3, tBuNC; L2 = dppm, dppe, dppp, bipy, phen, cod, nbd, or 1,4- diphenylbutadiene. Useful catalysts [CpRu(cod)X] were obtained by this method in 70-90 % yields. The structure of [CpRu(cod)I] was determined by X-ray diffraction. Reaction of 1 with Br- and allyl bromide afforded RuIV complex [CpRu(η3-C3H 5)]Br2. Cation 1 also was found to react with azide anion in the presence of bidentate phosphanes to afford [CpRuL2N 3] (L2 = dppm, dppe). Reaction of 1 with neutral ligands in the absence of nucleophilic anions proceeded under visible-light irradiation to give cationic complexes [CpRuL3]+ [L = CO, P(OMe) 3, P(OEt)3, tBuNC] in 80-90 % yields. Complex 1 (2 mol-%) catalyzed cyclotrimerization of dipropargyl Meldrum's acid with various alkynes RC≡CH [R = H, Bu, Hex, Ph, SiMe3, (CH2) 4C≡CH, (CH2)3OH, (CH2) 2Br, CH2OMe, CH2OAc, CH2NMeBoc] producing benzene derivatives in 50-85 % yields. According to DFT calculations, the attack of the first ligand (Cl- or L) is a rate-determining step in the naphthalene replacement in 1. The activation barrier for attack of the Cl- anion is ca. 10 kcal mol-1 lower in energy than that of the neutral ligands L = CO, MeNC, MeCN, thus providing a rationale for the faster reaction in the presence of halide anions. The barriers for naphthalene replacement in 1 were also found to be ca. 10-15 kcal mol-1 lower in energy than those for the benzene replacement in [CpRu(C6H 6)]+. The readily available (naphthalene)ruthenium complex 1 was shown to be a convenient precursor for various [CpRuL2X] complexes and an efficient catalyst for the cyclotrimerization of 1,6-diynes with assorted alkynes. Copyright

A new approach to enantiopure C3-symmetric molecules

Chiral base chemistry has been used to create three chiral centres in one pot on a C3-symmetric substrate. The potential of this new approach to C3-symmetric molecules is exemplified by the creation of an enantiopure C3v-symmetric triol, triphosphane and tripyridine. A ruthenium complex of the last compound has been studied by X-ray crystallography.

Chemo- and regioselective intermolecular cyclotrimerization of terminal alkynes catalyzed by cationic rhodium(I)/modified BINAP complexes: Application to one-step synthesis of paracyclophanes

A highly regioselective intermolecular cyclotrimerization of terminal alkynes has been developed based on the use of the cationic rhodium(I)/DTBM- Segphos complex. This method can be applied to a variety of terminal alkynes to provide 1,2,4-trisubstituted benzenes in high yield and with high regioselectivity. A chemo- and regioselective intermolecular crossed-cyclotrimerization of dialkyl acetylenedicarboxylates with a variety of terminal alkynes has also been developed based on the use of the cationic rhodium(I)/H8-BINAP complex, furnishing 3,6-disubstituted phthalates in high yields. It constitutes a highly efficient new method for intermolecular crossed-cyclotrimerization of two different monoynes in terms of catalytic activity, chemo- and regioselectivity, scope of substrates, and ease of operation. The versatility of this new crossed-alkyne cyclotrimerization procedure is demonstrated through its application to one-step synthesis of a [6]metacyclophane and [7]-[12]paracyclophanes from the corresponding terminal α,ω-diynes. Mechanistic studies have revealed that the chemo- and regioselectivity of this crossed-alkyne cyclotrimerization are determined by the preferential formation of a specific rhodium metallacycle derived from a terminal alkyne and a dialkyl acetylenedicarboxylate.