6947-14-4

Upstream product

• 17214-44-7 2-phenyl-4-pentenyl-1-amine 
• 5558-87-2 2-phenylpent-4-enenitrile 
• 67-56-1 methanol 
• 122348-55-4 5-nitro-4-phenylpentan-2-one 
• 122-57-6 1-Phenylbut-1-en-3-one 

Downstream Products

• 3274-54-2 2-methyl-4-phenyl-1H-pyrrole 

Relevant academic research and scientific papers

Group 4 Complexes Bearing Pyrrolide Ligand for Intramolecular Alkene Hydroamination and Activation of C≡N Bond

Titanium and zirconium complexes supported by a pyrrolide ligand HL1 [HL1 = 2-cyano-1H-pyrrole], Ti2(L2)2(NMe2)2 (1) and Zr3(L2)3(NMe2)6 (2) [L2 = N,N-dimethyl-1H-pyrrol-2-carboximidamide, NMe2-L1] were synthesized and characterized. The ligand L2 was generated by activation of C≡N bond of HL1 with HNMe2. In complex 1, two TiIV atoms are bridged by two nitrogen atoms. There are three characteristic ZrIV ions in 2, which are six-, seven- and six-coordinate, respectively. They were tested as catalysts for the intramolecular hydroamination of aminoalkenes, and the respective N-heterocycles were afforded in 74–99 % yields. Moreover, the formation of L2 ligand indicates that the amination of C≡N bond can be considered as a new and rapid way to synthesize other C–N bonds.

CCC-NHC Pincer Zr Diamido Complexes: Synthesis, Characterisation, and Catalytic Activity in Hydroamination/Cyclisation of Unactivated Amino-Alkenes,-Alkynes, and Allenes

2-(1,3-Bis-3′-butylimidazol-1′-yl-2′-ylidene)phenylene)bis(dimethylamido) iodo zirconium(iv) (3) and 2-(1,3-bis-3′-butylimidazol-1′-yl-2′-ylidene)phenylene)bis (dimethylamido) bromo zirconium(iv) (4), have been prepared via a modification of the solvent and stoichiometry from the previously reported methodology. The reactivity of 3 and 4 in hydroamination/cyclisation is reported. Both diamido complexes have been found to improve catalytic activity as compared with the previously reported mono-amido analogues. Complexes 3 and 4 were observed to be selective for primary amines over secondary amines in hydroamination/cyclisation. The lack of reactivity with secondary amines is consistent with a mechanism involving requisite formation of a Zr-imido intermediate.

Extreme π-Loading as a Design Element for Accessing Imido Ligand Reactivity. A CCC-NHC Pincer Tantalum Bis(imido) Complex: Synthesis, Characterization, and Catalytic Oxidative Amination of Alkenes

A rare Ta bis(imido) complex, which has unique reactivity, was prepared by manipulating the coordination sphere of a CCC-NHC pincer Ta complex. The reaction of lithium tert-butylamide with complex 1 yielded (1,3-bis(3′-butylimidazol-2′-yl-1′-idene)-2-phenylene)bis(tert-butylimido)tantalum(V) (2) as a lithium iodide bridged dimer, as determined by the X-ray structure. Complex 2 catalytically cyclized α,ω-aminoalkenes to effect an oxidative amination of alkenes (dehydrogenation by C-H activation) and produced a cyclic imine, an equivalent of reduced substrate, and varying proportions of hydroamination. Various additives and concentration impact the catalytic results. Computational and experimental observations have led to an initial mechanistic hypothesis. Based upon it, precatalyst 2 appears to be the first example of a bifunctional catalyst (MH-NHR) that is highly selective for nonpolar C=C bonds in preference to polar C=X bonds for outer-sphere hydrogenation.

Metal and halogen dependence of the rate effect in hydroamination/ cyclization of unactivated aminoalkenes: Synthesis, characterization, and catalytic rates of CCC-NHC hafnium and zirconium pincer complexes

1,3-Bis(3′-butylimidazol-1′-yl)benzene dibromide (2b) or 1,3-bis(3′-butylimidazol-1′-yl)benzene dichloride (2c) was reacted with a stoichiometric amount of Zr(NMe2)4 or Hf(NMe 2)4 yielding four new early transit

Highly enantioselective zirconium-catalyzed cyclization of aminoalkenes

Aminoalkenes are catalytically cyclized in the presence of cyclopentadienylbis(oxazolinyl)borato group 4 complexes {PhB(C5H 4)(OxR)2}M(NMe2)2 (M = Ti, Zr, Hf; OxR = 4,4-dimethyl-2-oxazoline, 4S-isopropyl-5,5- dimethyl-2-oxazoline, 4S-tert-butyl-2-oxazoline) at room temperature and below, affording five-, six-, and seven-membered N-heterocyclic amines with enantiomeric excesses of >90% in many cases and up to 99%. Mechanistic investigations of this highly selective system employed synthetic tests, kinetics, and stereochemistry. Secondary aminopentene cyclizations require a primary amine (1-2 equiv vs catalyst). Aminoalkenes are unchanged in the presence of a zirconium monoamido complex {PhB(C5H 4)(Ox4S-iPr,Me2)2}Zr(NMe2)Cl or a cyclopentadienylmono(oxazolinyl)borato zirconium diamide {Ph2B(C 5H4)(Ox4S-iPr,Me2)}Zr(NMe2) 2. Plots of initial rate versus [substrate] show a rate dependence that evolves from first-order at low concentration to zero-order at high concentration, and this is consistent with a reversible substrate-catalyst interaction preceding an irreversible step. Primary kinetic isotope effects from substrate conversion measurements (k′obs(H)/ k′obs(D) = 3.3 ± 0.3) and from initial rate analysis (k2(H)/k2(D) = 2.3 ± 0.4) indicate that a N-H bond is broken in the turnover-limiting and irreversible step of the catalytic cycle. Asymmetric hydroamination/cyclization of N-deutero-aminoalkenes provides products with higher optical purities than obtained with N-proteo-aminoalkenes. Transition state theory, applied to the rate constant k2 that characterizes the irreversible step, provides activation parameters consistent with a highly organized transition state (ΔS? = -43(7) cal·mol-1 K -1) and a remarkably low enthalpic barrier (ΔH ? = 6.7(2) kcal·mol-1). A six-centered, concerted transition state for C-N and C-H bond formation and N-H bond cleavage involving two amidoalkene ligands is proposed as most consistent with the current data.

Amidate ligand design effects in zirconium-catalyzed enantioselective hydroamination of aminoalkenes

In situ generated axially chiral zirconium biphenyl amidate complexes are efficient precatalysts for the enantioselective intramolecular hydroamination of aminoalkenes, generating α-substituted pyrrolidines and piperidine with up to 74% ee. Five new chelating amide proligands and three new zirconium amidate complexes have been prepared and fully characterized in this investigation of ligand structure/catalyst function. Solid-state molecular structures of the complexes suggest that the observed moderate and highly variable enantioselectivities are a consequence of the multiple isomers accessible to this family of complexes, including a κ2-(O,O)- bonding motif. Thermal stability studies of the complexes further revealed the tendency of these complexes to undergo diastereoselective dimerization to afford homochiral dimers. These dimeric precatalysts are less efficient when used for the cyclization of aminoalkenes in comparison to their monomeric precursors. These results illustrate the variable coordination modes accessible to amidate ligands and suggest steric factors that must be considered in advanced ligand design.

CCC-N-heterocyclic carbene pincer complexes: Synthesis, characterization and hydroamination activity of a hafnium complex

Our methodology for the stoichiometric preparation of CCC-NHC pincer complexes of Zr has been extended to Hf. The CCCBu-NHC pincer Hf complex has been characterized by X-ray crystal structure analysis. Catalytic activity in the intramolecular h

Intramolecular hydroamination of unbiased and functionalized primary aminoalkenes catalyzed by a rhodium aminophosphine complex

We report a rhodium catalyst that exhibits high reactivity for the hydroamination of primary aminoalkenes that are unbiased toward cyclization and that possess functional groups incompatible with more electrophilic hydroamination catalysts. The rhodium catalyst contains an unusual diaminophosphine ligand (L1) that binds to rhodium in a K3-P,O,P mode. The reactions catalyzed by this complex typically proceed at mild temperatures (room temperature to 70 °C) and occur with primary aminoalkenes lacking substituents on the alkyl chain that bias the system toward cyclization, with primary aminoalkenes containing chloride, ester, ether, enolizable ketone, nitrile, and unprotected alcohol functionality, and with primary aminoalkenes containing internal olefins. Mechanistic data imply that these reactions occur with a turnover-limiting step that is different from that of reactions catalyzed by late-transition-metal complexes of Pd, Pt, and Ir. This change in the turnover-limiting step and resulting high activity of the catalyst stem from favorable relative rates for protonolysis of the M-C bond to release the hydroamination product versus reversion of the aminoalkyl intermediate to regenerate the acyclic precursor. Probes of the origin of the reactivity of the rhodium complex of L1 imply that the aminophosphine groups lead to these favorable rates by effects beyond steric demands and simple electron donation to the metal center.

An improved method for the synthesis of zirconium (CCC-N-heterocyclic carbene) pincer complexes and applications in hydroamination

Upon heating Zr(NMe2)4, 1,3-bis(N-butyl-imidazolium) benzene diiodide and toluene analytically pure Zr pincer complex was obtained, which was found to be an intramolecular hydroamination catalyst. The Royal Society of Chemistry.

Bis(phosphinimino)methanide rare earth amides: Synthesis, structure, and catalysis of hydroamination/cyclization, hydrosilylation, and sequential hydroamination/hydrosilylation

A series of yttrium and lanthanide amido complexes [Ln{N-(SiHMe 2)2}2{CH(PPh2NSiMe3) 2}] (Ln = Y, La, Sm, Ho, Lu) were synthesized by three different pathways. The title compounds can be obtained either from [Ln{N(SiHMe 2)2}3(thf)2] and [CH 2(PPh2NSiMe3)2] or from KN-(SiHMe2)2 and [Ln(CH(PPh2NSiMe 3)2}-Cl2]2, while in a third approach the lanthanum compound was synthesized in a one-pot reaction starting from K{CH(PPh2NSiMe3)2}, LaCl3, and KN-(SiHMe2)2. All the complexes have been characterized by single-crystal X-ray diffraction. The new complexes, [Ln{N(SiHMe 2)2}2{CH(PPh2NSiMe3) 2}], were used as catalysts for hydroamination/cyclization and hydrosilylation reactions. A clear dependence of the reaction rate on the ionic radius of the center metal was observed, showing the lanthanum compound to be the most active one in both reactions. Furthermore, a combination of both reactions - a sequential hydroamination/hydrosilylation reaction - was also investigated.