1135446-30-8

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• 342819-91-4 2,2-diphenyl-6-heptenenitrile 
• 1119-51-3 bromopentene 
• 86-29-3 Diphenylacetonitrile 

Relevant academic research and scientific papers

A New N-Trityl-Substituted Aminopyridinato Titanium Catalyst for Hydroamination and Hydroaminoalkylation Reactions - Unexpected Intramolecular C-H Bond Activation

Sterically demanding 2,6-bis(tritylamino)pyridine is used for the synthesis of a mono(2,6-diaminopyridinato) titanium complex that undergoes unexpected intramolecular C-H bond activation to give access to an unusual 1-titanaisoindoline derivative. Both titanium complexes do not show high catalytic activity for hydroaminoalkylation reactions of alkenes but exceptional results are obtained in the field of alkene, alkyne, and allene hydroamination including room temperature activity for intramolecular alkene hydroamination, excellent regioselectivity of intermolecular alkyne and allene hydroamination as well as selectivity for hydroamination over hydroaminoalkylation during cyclization reactions of primary aminoalkenes.

Dearomatized BIAN alkaline-earth alkyl catalysts for the intramolecular hydroamination of hindered aminoalkenes

Reaction of a sterically encumbered bis(imino)acenapthene (dipp-BIAN) with either potassium alkyl or the heavier alkaline-earth dialkyl [Ae{CH(SiMe 3)2}2(THF)2] (Ae = Mg, Ca, Sr) reagents results in dearomatizat

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.

2-Aminopyridinate titanium complexes for the catalytic hydroamination of primary aminoalkenes

A series of mono(2-aminopyridinato)tris(dimethylamido) titanium complexes, ApTi(NMe2)3 (where Ap = 2-aminopyridinato), have been prepared via protonolysis, and their reactivity for the hydroamination of primary aminoalkenes has been explored. The Ti complex incorporating N,6-dimesityl-2-aminopyridinate as the supporting ancillary ligand has been shown to yield a catalyst suitable for room-temperature intramolecular hydroamination reactions to give gem-disubstituted five-and six-membered-ring products. The comparison of ApTi(NMe2)3 with other group 4 catalysts shows that controlling the steric environment at the metal center is the critical determining factor for hydroamination reactivity. The screening of known challenging primary aminoalkene substrates with the most reactive ApTi(NMe2)3 shows good breadth of reactivity for the reaction. This complex is not able to cyclize secondary aminoalkene substrates, suggesting this reaction proceeds via an intermediate imido [2+2] cycloaddition pathway. An Ap-supported Ti imido complex, which also exhibits hydroamination activity, has been prepared and fully characterized from ApTi(NMe 2)3 and 2,6-dimethylaniline.

Diamido-ether actinide complexes as catalysts for the intramolecular hydroamination of aminoalkenes

The synthesis and characterization of a series of new diamido-thorium(IV) and diamido-uranium(IV) halide and alkyl complexes supported by three different diamido-ether ligands are reported. Reaction of ThCl4?2DME with [(RNSiMe2)2O]Li2 ([RNON]Li 2) in DME when R = tBu gives [tBuNON]ThCl 5Li3?DME (1), when R = iPr2Ph in diethyl ether [iPr2Ph NON]ThCl3Li?DME (3) is prepared. Reaction of UCl4 with [iPr2Ph NON]Li2 in diethyl ether gives {[iPr2Ph NON]UCl2}2 (4). Reaction of ThCl4?2DME with Li2[( iPr2PhNCH2CH2)2O] ([iPr2Ph NCOCN]Li2) in DME gives [iPr2Ph NCOCN]ThCl2?DME (5). The addition of 2 equiv of LiCH 2SiMe3 to 1 and 5 resulted in salt- and base-free [ tBuNON]Th(CH2SiMe3)2 (7) and [iPr2Ph NCOCN]Th(CH2SiMe3)2 (9), respectively. Complexes 1, 3, 4, 7, and 9, as well as previously reported {[tBuNON]UCl2}2 (2), [tBuNON] U(CH2SiMe3)2 (6), and [iPr2Ph NCOCN]U(CH2SiMe3)2 (8) were examined as catalysts for the intramolecular hydroamination of a series of aminoalkenes. Complexes 6-9 were shown to facilitate the formation of 2-methyl-4,4- diphenylpyrrolidine from 2,2-diphenyl-1-amino-4-pentene at room temperature. For 9, this reaction occurs in less than 15 min, while for other dialkyls 6-8, the reaction takes less than 2 h. Dihalides 1 and 2 facilitated the same reaction at 60 °C in 4 h, while 3 and 4 showed no activity under the same conditions. Dialkyl complexes 7-9 were examined for further reactivity with different substrates. The uranium dialkyl 8 was more active than 7 and 9 for the cyclization of 2,2-diphenyl-1-amino-5-hexene and 2,2-diphenyl-1-amino-6-heptene, as well as more active in the cyclization of N-methyl-2,2-diphenyl-1-amino-4- pentene, a secondary amine. All three dialkyls became less active when the steric bulk of the gem-substituents was decreased from diphenyl to cyclopentyl; reactivity further decreased when the steric bulk of the substituents was decreased further to hydrogen.

Zirconium bis(pyridonate): A modified amidate complex for enhanced substrate scope in aminoalkene cyclohydroamination

A new bis(amidate)zirconium bis(amido) hydroamination pre-catalyst using 6-tert-butyl-3-phenyl-2-pyridone as a proligand has been prepared and characterized. This rare example of an early transition metal complex incorporating a 2-pyridonate derivative as an ancillary ligand was found to be effective for the cyclohydroamination of aminoalkenes, including more challenging substrates bearing unactivated internal CC bonds. The Royal Society of Chemistry.

Broadening the scope of group 4 hydroamination catalysis using a tethered ureate ligand

(Chemical Equation Presented) A broadly applicable group-4-based precatalyst for the hydroamination of primary and secondary amines was developed. Screening experiments involving a series of amide and urea proligands led to the discovery of a tethered bis(ureate) zirconium complex with unprecedented reactivity in the intermolecular hydroamination of alkynes and the intramolecular hydroamination of alkenes. This catalyst system is effective with primary and secondary amines, 1,2-disubstituted alkenes, and heteroatom-containing functional groups, including ethers, silanes, amines, and heteroaromatics. The gem-disubstituent effect is not required for cyclization. The catalyst is generally regioselective for the anti-Markovnikov product of intermolecular alkyne hydroamination, and chemoselective for hydroamination over C-alkylation when forming 6- and 7-membered rings from aminoalkenes.

Intramolecular hydroamination of aminoalkenes by calcium and magnesium complexes: A synthetic and mechanistic study

The β-diketiminate-stabilized calcium amide complex [{ArNC(Me)CHC(Me)NAr}Ca{N(SiMe3)2}-(THF)] (Ar = 2,6-diisopropylphenyl) and magnesium methyl complex [{ArNC(Me)CHC(Me)NAr}Mg(Me) (THF)] are reported as efficient precatalysts for hydroamination/cyclization of aminoalkenes. The reactions proceeded under mild conditions, allowing the synthesis of five-, six-, and seven-membered heterocyclic compounds. Qualitative assessment of these reactions revealed that the ease of catalytic turnover increases (i) for smaller ring sizes (5 > 6 > 7), (ii) substrates that benefit from favorable Thorpe-Ingold effects, and (iii) substrates that do not possess additional substitution on the alkene entity. Prochiral substrates may undergo diastereoselective hydroamination/cyclization depending upon the position of the existing stereocenter. Furthermore, a number of minor byproducts of these reactions, arising from competitive alkene isomerization reactions, were identified. A series of stoichiometric reactions between the precatalysts and primary amines provided an important model for catalyst initiation and suggested that these reactions are facile at room temperature, with the reaction of the calcium precatalyst with benzylamine proceeding with ΔG°(298 K) = -2.7 kcal mol-1. Both external amine/amide exchange and coordinated amine/amide exchange were observed in model complexes, and the data suggest that these processes occur via low-activation-energy pathways. As a result of the formation of potentially reactive byproducts such as hexamethyldisilazane, calcium-catalyst initiation is reversible, whereas for the magnesium precatalyst, this process is nonreversible. Further stoichiometric reactions of the two precatalysts with 1-amino-2,2-diphenyl-4-pentene demonstrated that the alkene insertion step proceeds via a highly reactive transient alkylmetal intermediate that readily reacts with N-H σ bonds under catalytically relevant conditions. The results of deuterium-labeling studies are consistent with the formation of a single transient alkyl complex for both the magnesium and calcium precatalysts. Kinetic analysis of the nonreversible magnesium system revealed that the reaction rate depends directly upon catalyst concentration and inversely upon substrate concentration, suggesting that substrate-inhibited alkene insertion is rate-determining.