Synthesis of allylamines
An efficient, enantioselective rhodium-catalyzed addition of potassium alkenyltrifluoroborates to N-nosyl aliphatic imines offers good reaction yields and excellent enantioselectivities for various aliphatic imines and nucleophilic alkenyltrifluoroborates.
X.-W. Qian, Z.-J. Xue, Q. Zhao, Z. Cui, Y.-J. Chen, C.-G. Feng, G.-Q. Lin, Org. Lett., 2017, 19, 5601-5604.
An efficient rhodium-catalyzed asymmetric addition reaction of potassium alkenyltrifluoroborates to N-nosylaldimines proceeded with good to excellent yields and excellent enantioselectivities. The utility of this method is demonstrated by the formal synthesis of (-)-aurantioclavine.
Z. Cui, Y.-J. Chen, W.-Y. Gao, C.-G. Feng, G.-Q. Lin, Org. Lett., 2014, 16, 1016-1019.
N-tosyl aryl aldimines can be used as substrates in a rhodium-catalyzed enantioselective 1,2-addition reaction using alkenylboron nucleophiles. Addition of various potassium alkenyltrifluoroborates to aryl aldimines furnished the corresponding chiral allylic amines in good yield and high ee. This method efficiently provides di-, tri-, and tetrasubstituted allylic N-tosyl amines with high asymmetric induction.
B. Gopula, C.-W. Chiang, W.-Z. Lee, T.-S. Kuo, P.-Y. Wu, J. P. Henschke, H.-L. Wu, Org. Lett., 2014, 16, 632-635.
The use of a non-C2-symmetric ProPhenol ligands enables a catalytic and asymmetric vinylation of N-Boc imines via hydrozirconation providing allylic amines in excellent yields and enantioselectivities. A very short, asymmetric synthesis of the selective serotonine reuptake inhibitor (SSRI) (-)-dapoxetine is also reported.
B. M. Trost, C.-I Hung, D. C. Koester, Y. Miller, Org. Lett., 2015, 17, 3778-3781.
The reaction between N-Boc-aminals and organomagnesium reagents provides previously inaccessible N-Boc-protected propargylic and allylic amines via in situ generated N-Boc-imine intermediates. The obtained N-Boc-propargylic amines could be readily converted into unprecedented N-Boc-ketimines by oxidation with manganese dioxide.
T. Kano, R. Kobayashi, K. Maruoka, Org. Lett., 2016, 18, 276-279.
The union of vinyl sulfones with photoredox-generated α-amino radicals enables direct C-H vinylations of N-aryl tertiary amines, as well as decarboxylative vinylations of N-Boc α-amino acids, to provide allylic amines of broad diversity in high yield and with excellent olefin geometry control. The utility of this reaction has been demonstrated via the syntheses of several natural products and a number of established pharmacophores.
A. Noble, D. W. C. MacMillan, J. Am. Chem. Soc., 2014, 136, 11602-11605.
A CO2 extrusion, nickel capture, migratory insertion sequence with terminal and internal alkynes provides stereodefined functionalized olefins from carboxylic acids. A hydrogen atom transfer enables even a direct vinylation of unactivated C-H bonds.
N. A. Till, R. T. Smith, D. W. C. MacMillan, J. Am. Chem. Soc., 2018, 140, 5701-5705.
Exposure of various N-arylsulfonyl aldimines to 2-butyne and hydrogen at ambient pressure in the presence of a cationic iridium(I) catalyst modified by BIPHEP provides reductive coupling products, allylic amines, in good yields as single geometrical isomers. Nonsymmetric alkynes couple under standard conditions with high levels of regioselection.
A. Barchuk, M.-Y. Ngai, M. J. Krische, J. Am. Chem. Soc., 2007, 129, 8432-8433.
Using an iridium catalyst modified by (R)-Cl,MeO-BIPHEP, the hydrogenating of alkynes in the presence of N-arylsulfonyl imines delivers the corresponding allylic amines in highly optically enriched form. This protocol circumvents the use of preformed vinyl metal reagents and is applicable to aromatic, heteroaromatic, and aliphatic N-arylsulfonyl aldimines.
M.-Y. Ngai, A. Barchuk, M. J. Krische, J. Am. Chem. Soc., 2007, 129, 12644-12645.
A highly efficient three-component coupling reaction between thioformamides and organolithium and Grignard reagents was developed. The generality of the process has been demonstrated by using various combinations of reactants and reagents.
T. Murai, F. Asai, J. Am. Chem. Soc., 2007, 129, 780-781.
A hydrovinylation of N-acetylenamines with ethylene is catalyzed by a ruthenium hydride complex, RuHCl(CO)(PCy3)2, providing a series of N-acetylamines with a quaternary carbon center with up to 99% yield.
Q.-S. Wang, J.-H. Xie, W. Lei, S.-F. Zhu, L.-X. Wang, Q.-L. Zhou, Org. Lett., 2011, 13, 3388-3391.
A reductive alkenylation of secondary amides with enamines provides allylamines using trifluoromethanesulfonic anhydride as an amide activation reagent and enamines as unconventional alkenylation reagents.
A.-E. Wang, C.-C. Yu, T.-T. Chen, Y.-P. Liu, P.-Q. Huang, Org. Lett., 2018, 20, 999-1002.
Exposure of aromatic and aliphatic N-arylsulfonyl aldimines to equal volumes of acetylene and hydrogen gas at 45°C and ambient pressure in the presence of chirally modified cationic rhodium catalysts provides (Z)-dienyl allylic amines in highly optically enriched form and as single geometrical isomers.
E. Skucas, J. R. Kong, M. J. Krische, J. Am. Chem. Soc., 2007, 129, 7242-7243.
An efficient method for the preparation of various 2-aminomethyl-1,3-dienes was developed through the reaction of imines with an organoindium reagent generated in situ from indium and 1,3-dibromo-2-butyne. Three-component reactions of aldehydes, amines, and organoindium reagents gave successful results in a one-pot process.
D. Seomoon, J. A, P. H. Lee, Org. Lett., 2009, 11, 2401-2404.
Low loadings of an in situ generated B-based catalyst, that is derived from a simple, robust, and readily accessible chiral aminoalcohol, promote an enantioselective addition of an allene unit to aldimines. Various aryl-, heteroaryl-, and alkyl-substituted homoallenylamides can be obtained in very good yield and high enantiomeric excess at ambient temperature using a commercially available allenylboron reagent.
H. Wu, F. Haeffner, A. H. Hoveyda, J. Am. Chem. Soc., 2014, 136, 3780-3781.
Catalytic Asymmetric Aza-Morita-Baylis-Hillman Reaction of Methyl Acrylate: Role of a Bifunctional La(O-iPr)3/Linked-BINOL Complex
T. Yukawa, B. Seelig, Y. Xu, H. Morimoto, Y. Xu, H. Morimoto, S. Matsunaga, A. Berkessel, M. Shibasaki, J. Am. Chem. Soc., 2010, 132, 11988-11992.
(S)-3-[2-(Diphenylphosphino)phenyl]BINOL is an efficient asymmetric bifunctional organocatalyst for the aza-Morita-Baylis-Hillman reaction. The Brønsted acid and Lewis base functionalities cooperate in substrate activation to promote the reaction with high enantiocontrol.
K. Matsui, S. Takizawa, H. Sasai, Synlett, 2006, 761-765.
(S)-3-(N-Isopropyl-N-3-pyridinylaminomethyl)BINOL is an efficient, bifunctional organocatalyst for the enantioselective aza-Morita-Baylis-Hillman (aza-MBH) reaction. The acid-base-mediated functionalities for the activation of the substrate and the fixing of conformation of the organocatalyst are harmoniously performed to promote the reaction with high enantiocontrol.
K. Matsui, S. Takizawa, H. Sasai, J. Am. Chem. Soc., 2005, 127, 3680-3681.
Chiral Bifunctional Organocatalysts in Asymmetric Aza-Morita-Baylis-Hillman Reactions of Ethyl (Arylimino)acetates with Methyl Vinyl Ketone and Ethyl Vinyl Ketone
M. Shi, G.-N. Ma, J. Gao, J. Org. Chem., 2007, 72, 9779-9781.
Allylic N-sulfonylamines are synthesized in high yields and with high regioselectivities by reaction of N-sulfonylaziridines with excess dimethylsulfonium methylide.
D. M. Hodgson, M. J. Fleming, S. J. Stanway, Org. Lett., 2005, 7, 3295-3298.
Opening of the epoxide ring of enantiopure (2R,1'S)-2-(1-aminoalkyl)epoxides with different organolithium compounds gave allylamines with total selectivity and in high yields.
J. M. Concellon, J. R. Suarez, V. del Solar, Org. Lett., 2006, 8, 349-351.
The reaction of various aromatic nitriles and conjugated alkenenitriles with 1.1 equiv of Ti(OiPr)4 and 2.2 equiv of EtMgBr followed by addition of a Lewis acid gave 1-arylcyclopropylamines and 1-alkenylcyclopropylamines in good yields.
P. Bertus, J. Szymoniak, J. Org. Chem., 2003, 68, 7133-7136.