- Hydrogen-Bond-Promoted Metal-Free Hydroamination of Alkynes
-
An original metal-free regio- A nd stereoselective intermolecular hydroamination of alkynes is described. Various (E)-enamines were obtained from arylacetylenes and aliphatic secondary amines in the presence of ethylene glycol as a solvent. The latter is
- Bahri, Janet,Monnier, Florian,Ollevier, Thierry,Taillefer, Marc,Tanbouza, Nour
-
supporting information
p. 2086 - 2090
(2019/11/05)
-
- Regio- and Enantioselective Formal Hydroamination of Enamines for the Synthesis of 1,2-Diamines
-
The asymmetric formal hydroamination of enamines using a CuH catalyst is reported. The method provides a straightforward and efficient approach to the synthesis of chiral 1,2-dialkyl amines in good yields with high levels of enantioselectivities for a broad range of substrates, and should have significant value for the preparation of molecules bearing a 1,2-diamine motif.
- Yu, Lu,Somfai, Peter
-
supporting information
p. 8551 - 8555
(2019/05/21)
-
- The pyrrole ring η2-hapticity bridged binuclear tricarbonyl Mo(0) and W(0) complexes: catalysis of regioselective hydroamination reactions and DFT calculations
-
Following the report of the ferrocene structure, metal complexes containing the heteroatom-substituted cyclopentadienyl (Cp) analogue, that is the η5 pyrrolyl ligand, have been reported. While the Cp ligand continues to be a favorite ligand in
- Jha, Vikesh Kumar,Mani, Ganesan,Davuluri, Yogeswara Rao,Anoop, Anakuthil
-
supporting information
p. 1840 - 1847
(2017/02/23)
-
- Dynamic Covalent Chemistry of Aldehyde Enamines: BiIII- and ScIII-Catalysis of Amine–Enamine Exchange
-
The dynamic exchange of enamines from secondary amines and enolizable aldehydes has been demonstrated in organic solvents. The enamine exchange with amines was efficiently catalyzed by Bi(OTf)3 and Sc(OTf)3 (2 mol %) and the equilibria (60 mm) could be attained within hours at room temperature. The formed dynamic covalent systems displayed high stabilities in basic environment with 2 % by-product formation within one week after complete equilibration. This study expands the scope of dynamic C?N bonds from imine chemistry to enamines, enabling further dynamic methodologies in exploration of this important class of structures in systems chemistry.
- Zhang, Yang,Xie, Sheng,Yan, Mingdi,Ramstr?m, Olof
-
supporting information
p. 11908 - 11912
(2017/09/07)
-
- An Efficient One–pot Procedure for the Direct Preparation of 4,5-Dihydroisoxazoles from Amides
-
A Mo(CO)6 (molybdenumhexacarbonyl) catalyzed reductive functionalization of amides to afford 5-amino substituted 4,5-dihydroisoxazoles is presented. The reduction of amides generates reactive enamines, which upon the addition of hydroximinoyl chlorides and base undergoes a 1,3-dipolar cycloaddition reaction that gives access to the desired heterocyclic compounds. The transformation of amides is highly chemoselective and tolerates functional groups such as nitro, nitriles, esters, and ketones. Furthermore, a versatile scope of 4,5-dihydroisoxazoles derived from a variety of hydroximinoyl chlorides and amides is demonstrated. (Figure presented.).
- Slagbrand, Tove,Kervefors, Gabriella,Tinnis, Fredrik,Adolfsson, Hans
-
p. 1990 - 1995
(2017/06/09)
-
- Facile preparation of pyrimidinediones and thioacrylamides: Via reductive functionalization of amides
-
The development of an efficient protocol for the reductive functionalization of amides into pyrimidinediones and amino-substituted thioacrylamides is presented. Enamines are generated in a highly chemoselective amide hydrosilylation reaction catalyzed by
- Trillo, Paz,Slagbrand, Tove,Tinnis, Fredrik,Adolfsson, Hans
-
p. 9159 - 9162
(2017/08/17)
-
- 1,3-Dipolar cycloaddition reactivities of perfluorinated aryl azides with enamines and strained dipolarophiles
-
The reactivities of enamines and predistorted (strained) dipolarophiles toward perfluoroaryl azides (PFAAs) were explored experimentally and computationally. Kinetic analyses indicate that PFAAs undergo (3 + 2) cycloadditions with enamines up to 4 orders of magnitude faster than phenyl azide reacts with these dipolarophiles. DFT calculations were used to identify the origin of this rate acceleration. Orbital interactions between the cycloaddends are larger due to the relatively low-lying LUMO of PFAAs. The triazolines resulting from PFAA-enamine cycloadditions rearrange to amidines at room temperature, while (3 + 2) cycloadditions of enamines and phenyl azide yield stable, isolable triazolines. The 1,3-dipolar cycloadditions of norbornene and DIBAC also show increased reactivity toward PFAAs over phenyl azide but are slower than enamine-azide cycloadditions.
- Xie, Sheng,Lopez, Steven A.,Ramstr?m, Olof,Yan, Mingdi,Houk
-
supporting information
p. 2958 - 2966
(2015/03/18)
-
- Efficient and selective synthesis of e-vinylamines via tungsten(0)-catalyzed hydroamination of terminal alkynes
-
The hydroamination of terminal alkynes (RC≡CH=phenylacetylene, 4-methylphenylacetylene, 4-fluorophenylacetylene, 1-hexyne, methyl 2-propynyl ether, prop-2-yn-1-ol) with secondary amines (piperidine, pyrrolidine, morpholine, piperazine, methylpiperazine, 4
- Kocicka, Paulina,Czelusniak, Izabela,Szymaska-Buzar, Teresa
-
supporting information
p. 3319 - 3324
(2015/01/09)
-
- Catalytic reductive dehydration of tertiary amides to enamines under hydrosilylation conditions
-
Tertiary amides are efficiently reduced to their corresponding enamines under hydrosilylation conditions, using a transition-metal-free catalytic protocol based on t-BuOK (5 mol %) and (MeO)3SiH or (EtO) 3SiH as the reducing agent. The enamines were formed with high selectivity in good-to-excellent yields.
- Volkov, Alexey,Tinnis, Fredrik,Adolfsson, Hans
-
supporting information
p. 680 - 683
(2014/03/21)
-
- Inverse electron demand hetero-Diels-Alder reaction in preparing 1,4-benzodioxin from o-quinone and enamine
-
A process for synthesizing 1,4-benzodioxin, through oxidation of a phenol to an o-quinone followed by treatment with an enamine, has been developed. Adduct stereochemistry is found to be retained via this one-pot reaction. The method uses hypervalent iodine reagent under mild conditions and is compatible with a wide scope of phenols and enamines.
- Zhang, Jinsong,Taylor, Chris,Bowman, Erich,Savage-Low, Leo,Lodewyk, Michael W.,Hanne, Larry,Wu, Guang
-
supporting information
p. 6298 - 6302
(2013/11/06)
-
- Rhodium-catalyzed anti-markovnikov addition of secondary amines to arylacetylenes at room temperature
-
An efficient method for synthesis of E-enamines by the anti-Markovnikov addition of secondary amines to terminal alkynes is described. The reaction of a variety of aryl- and heteroarylacetylenes proceeded at room temperature using a combination of a 8-quinolinolato rhodium complex and P(p-MeOC6H 4)3 as a catalyst. The products were obtained as enamines by simple bulb-to-bulb distillation.
- Sakai, Kazunori,Kochi, Takuya,Kakiuchi, Fumitoshi
-
supporting information; scheme or table
p. 3928 - 3931
(2011/10/01)
-
- Isolation of catalytic intermediates in hydroamination reactions: Insertion of internal alkynes into a zirconium-amido bond
-
Insert alkyne to continue: Reaction of a bis(ureate) zirconium dimethylamido complex with electron-rich alkynes leads to vinylamine insertion products (see scheme). The insertion of C=C unsaturated bonds into M=N bonds is proposed as a key step in lanthan
- Leitch, David C.,Turner, Courtney S.,Schafer, Laurel L.
-
supporting information; experimental part
p. 6382 - 6386
(2010/12/19)
-
- 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.
- Leitch, David C.,Payne, Philippa R.,Dunbar, Christine R.,Schafer, Laurel L.
-
supporting information; experimental part
p. 18246 - 18247
(2010/04/25)
-
- Highly efficient synthesis of aldenamines from carboxamides by iridium-catalyzed silane-reduction/dehydration under mild conditions
-
The combination of IrCl(CO)(PPh3)2 with 1,1,3,3-tetramethyldisiloxane or poly(methylhydrosiloxane) (PMHS) is found to be an efficient catalyst system for the preparation of aldenamines from carboxamides; in particular, facile removal of silicone and iridium residues from the product can be achieved by the use of PMHS.
- Motoyama, Yukihiro,Aoki, Masaharu,Takaoka, Naoki,Aoto, Ryuta,Nagashima, Hideo
-
supporting information; experimental part
p. 1574 - 1576
(2009/09/06)
-
- (t-Bu)2PN=P(i-BuNCH2CH2)3N: New efficient ligand for palladium-catalyzed C-N couplings of aryl and heteroaryl bromides and chlorides and for vinyl bromides at room temperature
-
(Chemical Equation Presented) By employing Pd(OAc)2, Cs 2CO3, or NaOH, and the new ligand (t-Bu) 2PN=P(i-BuNCH2CH2)3N (3a), an electronically diverse array of aryl bromides and chlorides possessing base-sensitive substituents (nitro, ester, and keto) provide coupling products with bulky aryl amines in good to excellent yields. Aryl halides possessing other functional groups including cyano, amino, trifluoromethyl, and phenol, coupled with equal ease, producing highly functionalized amines in good to excellent yields. Moreover, an aryl chloro group can be preserved in the presence of a bromo substituent under our reaction conditions. BOC-protected amines also participated efficiently. Heterocyclic bromides and chlorides underwent clean couplings with amines in excellent yields. An important strength of our protocol is the use of lower palladium loadings than those reported earlier, without compromising yields. The air-stable palladium complex (η3-cinnamyl)PdCl·(3a) (5) was also employed successfully in C-N coupling reactions while the crotyl analogue was less efficacious. The 3a/Pd(OAc)2 catalyst system promotes, for the first time, efficient coupling of vinyl bromides with a variety of amines to produce imines and enamines at room temperature.
- Reddy, Ch. Venkat,Kingston, Jesudoss V.,Verkade, John G.
-
p. 3047 - 3062
(2008/09/19)
-
- Multicomponent and one-pot synthesis of trisubstituted pyridines through a Pd-catalyzed cross-coupling/cross-coupling/cycloaddition sequence
-
Trisubstituted pyridines are regioselectively synthesized through multicomponent and one-pot processes promoted by a bifunctional Pd-catalyst. The process involves formation of an enamine by Pd-catalyzed amination of an alkenyl bromide, formation of a 2-aza-1,3-butadiene by Pd-catalyzed cross-coupling of a trimethylsilylimine with an alkenyl bromide, and Lewis acid catalyzed cycloaddition between the enamine and the azadiene.
- Barluenga, José,Jiménez-Aquino, Agustín,Fernández, M. Alejandro,Aznar, Fernando,Valdés, Carlos
-
p. 778 - 786
(2008/04/12)
-
- Highly chemoselective formation of aldehyde enamines under very mild reaction conditions
-
Although ketone enamines are widely used in organic synthesis, aldehyde enamines are rarely employed due to the limitations of their preparation using known methods (need for acid or base, excess of amine, and/or elevated temperature). We have successfull
- Belanger, Guillaume,Dore, Michael,Menard, Frederic,Darsigny, Veronique
-
p. 7481 - 7484
(2007/10/03)
-
- A highly effective catalyst system for the Pd-catalyzed amination of vinyl bromides and chlorides
-
(Chemical Equation Presented) A highly efficient synthesis of enamines and imines by Pd-catalyzed amination of vinyl bromides or chlorides with amines is described using the Pd2(dba)3/P(i-BuNCH2CH 2)3N catalyst system.
- Reddy, Chinta Reddy Venkat,Urgaonkar, Sameer,Verkade, John G.
-
p. 4427 - 4430
(2007/10/03)
-
- Palladium-Catalyzed Cross-Coupling Reactions of Amines with Alkenyl Bromides: A New Method for the Synthesis of Enamines and Imines
-
The palladium-catalyzed cross-coupling reaction of alkenyl bromides with secondary and primary amines gives rise to enamines and imines, respectively. This new transformation expands the applicability of palladium-catalyzed C-N bond forming reactions (the Buchwald-Hartwig amination), which have mostly been applied to aryl halides. After screening of different ligands, bases, and solvents, the catalytic combination [Pd2(dba)3]/BINAP in the presence of NaOtBu in toluene gave the best results in the cross-coupling of secondary amines with 1-bromostyrene (dba=dibenzylideneacetone, BINAP=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl). The corresponding enamines are obtained cleanly and in nearly quantitative yields. However, steric hindrance seems to be a limitation of the reaction, as amines carrying large substituents are not well converted. The same methodology can be applied to the coupling of secondary amines with 2-bromostyrene. Moreover, the reaction with substituted 2-bromopropenes allows regioselective synthesis of isomerizable terminal enamines without isomerization of the double bond. The best catalytic conditions for the cross-coupling of 1-bromostyrene with primary amines include again the use of the Pd°/BINAP/NaOtBu system. The reaction gives rise to the expected imines in very short times and with low catalyst loadings. A set of structurally diverse imines can be prepared by this methodology through variations in the structure of both coupling partners. However, 2-bromostyrene failed to give good results in this coupling reaction, probably due to product inhibition of the catalytic cycle. Competition experiments of vinyl versus aryl amination reveal that the reaction occurs preferentially on vinyl bromides.
- Barluenga, Jose,Fernandez, M. Alejandro,Aznar, Fernando,Valdes, Carlos
-
p. 494 - 507
(2007/10/03)
-
- Rhodium-catalyzed anti-Markovnikov hydroamination of vinylarenes
-
The transition metal-catalyzed anti-Markovnikov hydroamination of unactivated vinylarenes with a rhodium complex of DPEphos is reported. The reaction of electron-neutral or electron-rich vinylarenes with a variety of secondary amines in the presence of catalyst forms the products from anti-Markovnikov hydroamination in high yields. Reactions of morpholine, N-phenylpiperazine, N-Boc-piperazine, piperidine, 2,5-dimethylmorpholine, and perhydroisoquinoline reacted with styrene to form the amine product in 51-71% yield. Reactions of a variety of vinylarenes with morpholine generated amine as the major product. Reactions of morpholine with electron-poor vinylarenes gave lower amine:enamine ratios than reactions of electron-rich vinylarenes at the same concentration of vinylarene, but conditions were developed with lower concentrations of electron-poor vinylarene to maintain formation of the amine as the major product. Reactions of dimethylamine with vinylarenes were fast and formed amine as the major product. Mechanistic studies on the hydroamination process showed that the amine:enamine ratio was lower for reactions conducted with higher concentrations of vinylarene and that one vinylarene influences the selectivity for reaction of another. A mechanism proceeding through a metallacyclic intermediate that opens in the presence of a second vinylarene accounts for these and other mechanistic observations. Copyright
- Utsunomiya, Masaru,Kuwano, Ryoichi,Kawatsura, Motoi,Hartwig, John F.
-
p. 5608 - 5609
(2007/10/03)
-
- Novel method for the synthesis of enamines by palladium catalyzed amination of alkenyl bromides
-
The intermolecular palladium catalyzed cross-coupling reaction between secondary amines and alkenyl bromides is described for the first time, giving rise to enamines with very high yields and regioselectivity.
- Barluenga, Jose,Fernandez, M. Alejandro,Aznar, Fernando,Valdes, Carlos
-
p. 2362 - 2363
(2007/10/03)
-
- A convenient rhodium-catalyzed intermolecular hydroamination procedure for terminal alkynes
-
The first rhodium-catalyzed intermolecular hydroamination of alkynes is presented. Terminal alkynes react efficiently with anilines in the presence of cationic rhodium(I) catalysts under very mild reaction conditions (e.g., base and acid free at room temperature) to yield up to 99% of the corresponding imines. An easy one-pot protocol for the synthesis of secondary amines was developed by combining this alkyne amination reaction with in situ addition of organolithium reagents.
- Hartung,Tillack,Trauthwein,Beller
-
p. 6339 - 6343
(2007/10/03)
-
- Rhodium-catalyzed amination of aromatic olefins [1]
-
The oxidative amination of styrene with secondary amines in the presence of cationic rhodium catalysts yields regiospecifically the corresponding anti-Markovnikov enamines. Styrene as the hydrogen acceptor gave concomitantly ethylbenzene. In the presence
- Tillack, Annegret,Trauthwein, Harald,Hartung, Christian G.,Eichberger, Martin,Pitter, Stephan,Jansen, Achim,Beller, Matthias
-
p. 1327 - 1334
(2007/10/03)
-
- The first rhodium-catalyzed anti-markovnikov hydroamination: Studies on hydroamination and oxidative amination of aromatic olefins
-
The first transition-metal-catalyzed regiospecific anti-Markovnikov hydroamination of aromatic olefins is reported. Styrene and substituted styrenes react with secondary aliphatic amines, especially morpholine and Narylpiperazines, in the presence of cationic rhodium complexes to give 2- aminoethenylbenzene and 2-aminoethylbenzene derivatives. Cationic [Rh(cod)2]+BF4- and various phosphines (l:2-mixture) were employed as in situ catalysts. According to labeling experiments, there is no evidence that the hydroamination is a consecutive hydrogenation of a previously formed enamine. Hydroamination with simple secondary amines, for example piperidine, can also be achieved by the use of a higher olefin concentration and higher reaction temperatures than those given in previously published reaction procedures. Kinetic investigations of the major reaction pathway reveal that the reaction rate of the oxidative amination and the hydroamination is dependent on the styrene and on the catalyst concentration, and independent of the amine concentration. Experiments that employed deuterium-labeled amines (N-D) provided evidence that the mechanism involves an amine- activating pathway. The substituents on the styrene, the phosphine ligand, and the solvent influence the yield of the aminations and the enamine:alkylamine ratio.
- Beller,Trauthwein,Eichberger,Breindl,Herwig,Mueller,Thiel
-
p. 1306 - 1319
(2007/10/03)
-
- Amination of aryl- and vinylacetylenic compounds catalyzed by rhodium(I) complexes
-
New rhodium-catalyzed amination reactions of arylacetylenes and cyclohexen-1-ylacetylene in the presence of strong bases with the use of carbon dioxide as an auxiliary are described. Secondary amines attack the terminal carbon atom of the triple bond followed by protonation of the adjacent carbon atom. Alternatively, the reaction can proceed further with the addition of the second alkyne molecule. The conditions for the selective synthesis of enamines (up to 87% yield) or α-substituted propynylamines (up to 86% yield) are reported.
- Costa,Chiusoli,Gaetti,Gabriele,Salerno
-
p. 936 - 940
(2007/10/03)
-
- Indium-mediated reactions of enamines in the presence of acid
-
The reaction of enamines with allyl bromide and metallic indium in THF to afford homoallylamines was greatly accelerated by the addition of one equivalent of a suitable carboxylic acid, such as acetic acid. It was established that the likely mechanism con
- Tussa, Laurent,Lebreton, Chrystele,Mosset, Paul
-
p. 1064 - 1070
(2007/10/03)
-
- Novel Two-Step Stereoselective Synthesis of (E)-Enamines and 1-Amino-1,3-dienes from Terminal Alkynes
-
(E)-Enamines and 1-amino-1,3-dienes have been prepared by reaction of secondary amines with alk-1-en-1-yl acetates resulting from the ruthenium-catalyzed anti-Markovnikov addition of acetic acid to terminal alkynes and enynes.
- Doucet, Henri,Bruneau, Christian,Dixneuf, Pierre H.
-
p. 807 - 808
(2007/10/03)
-
- Synthesis and reactions of chloroazodienes. A new and general synthesis of pyridazines
-
The reaction of dichlorohydrazones with Hunig's base gives 4-chloroazodienes, which were found to combine with a variety of electron rich olefins to yield chloro-substituted tetrahydropyridazines. These chloroazodiene cyclizations are best characterized a
- South, Michael S.,Jakuboski, Terri L.
-
p. 5703 - 5706
(2007/10/02)
-
- Electrochemical Cyclization of 1-Phenyl-2(-1'-chlorophenyl)-substituted Five-membered Nitrogen Heterocycles. Application to the Synthesis of Phenanthridines
-
Pyrrolophenanthridine (compound 4), 3-phenylimidazophenanthridine 8, tetrazolophenanthridine 11 and benzotetrazolophenanthridine 12 have been prepared using an electrochemical cyclizatin procedure.Treatment of the imidazophenanthridine with singlet oxygen yields a phenanthridone by degradation of the heterocyclic system.Lithium aluminium hydride reduction of the tetrazolophenanthridines yields the phenanthridine.
- Grimshaw, James,Hewitt, S. Armstrong
-
p. 2995 - 2998
(2007/10/02)
-
- SYNTHESIS OF A PROSTAGLANDIN ENDOPEROXIDE MODEL COMPOUND AND ITS REACTION WITH ELECTRON TRANSFER REAGENTS
-
5-Exo-phenyl-2,3-dioxabicycloheptane (4c) was synthesized as a model compound of prostaglandin endoperoxide (PGH) to mimic the bioconversion of PGH into thromboxane (TX).The reaction of (4c) with various electron transfer reagents was investigated.With the aid of a catalytic amount of ferrous ion, (4c) was successfully converted into the thromboxane B (TXB) skeleton.
- Takahashi, Kimio,Kishi, Morio
-
p. 4737 - 4746
(2007/10/02)
-
- Enamine synthesis using the Horner-Wittig reaction. Part 1. (Aminomethyl)diphenylphosphine oxides, new formyl anion equivalents
-
Using the Horner-Wittig reagent (morpholinomethyl)diphenylphosphine oxide (7), aromatic, aliphatic and α,β-unsaturated aldehydes are converted into morpholino enamines of their homologous aldehydes.With diphenylphosphine oxide (12), the same aldehydes, together with the ketones (cyclic as well as acyclic, both saturated and α,β-unsaturated), are converted into enamines of their homologous aldehydes.Both types of enamines are converted into the corresponding aldehydes by mild, acid-catalyzed hydrolysis, showing the utility of 7 and 12, as formyl anion equivalents.Preparation of each geometrical isomer of the N-methylanilino enamines is possible since the intermediate diastereoisomeric adducts 13 can be separated.
- Broekhof, N. L. J. M.,Gen, A. van der
-
p. 305 - 312
(2007/10/02)
-
- Inverse Electron Demand Diels-Alder Reactions of 4,6-Dimethyl-2-oxo-2H-pyran-5-carboxylic Acid Esters and Morpholino Enamines: Regiospecific Preparation of 3- or 4-Substituted-2,6-dimethylbenzoates
-
Previously, α-pyrones have been used as dienes in cycloaddition reactions with enamines to form adducts that, upon eliminationof carbon dioxide via a cycloreversion reaction and concomitant aromatization through amine elimination, provided sustituted aryl
- Gingrich, Henry L.,Roush, David M.,Saun, William A. Van
-
p. 4869 - 4873
(2007/10/02)
-
- Reactions of 2,2,2-Trichloroethylamines with Grignard Reagents and Alkyllithiums
-
2,2,2-Trichloro- and 2,2-dichloroethylamines were found to suffer monoalkylation with Grignard reagents and alkyllithiums giving, in the main, chain-lenghtened β,γ- or α,β-unsaturated amines.Which product is formed depends upon the individual structures o
- Takamatsu, Masanori,Terao, Yoshiyasu,Sekiya, Minoru
-
p. 2682 - 2687
(2007/10/02)
-