Synthesis of alkylamines
Various N-toluenesulfonylimines were successfully ethylated with diethylzinc in the presence of copper(II) ditriflate and a chiral amidophosphine ligand in toluene to give the corresponding N-toluenesulfonylamides in good yields and high enantioselectivity.
T. Soeta, K. Nagai, H. Fujihara, M. Kuriyama, K. Tomioka, J. Org. Chem., 2003, 59, 9655-9659.
The synthesis of free α-chiral amines by a one-pot multicomponent procedure involves the formation of N-diphenylphosphinoylimines from commercially available starting materials and the subsequent enantioselective addition of diakylzinc reagents using an air-stable precatalyst complex.
A. Cote, A. B. Charette, J. Org. Chem., 2005, 70, 10864-10867.
A one-pot reaction for the transformation of common secondary amides into amines with C-C bond formation consists of in situ amide activation with Tf2O followed by partial reduction and addition of C-nucleophiles. The method is general in scope and allows the use of both hard nucleophiles (RMgX, RLi) and soft nucleophiles, as well as enolates. With soft nucleophiles the presence of ester, cyano, nitro, and tertiary amide groups are tolerated.
P.-Q. Huang, Y.-H. Huang, K.-J. Xiao, Y. Wang, X.-E. Xia, J. Org. Chem., 2015, 80, 2861-2868.
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.
A ligand-controlled, nickel-catalyzed cross-coupling of aliphatic N-tosylaziridines with aliphatic organozinc reagents offers complete regioselectivity for reaction at the less hindered C-N bond, and the products are furnished in very good yield for a broad selection of substrates. The air-stable nickel(II) chloride/ligand precatalyst can be handled and stored outside a glovebox.
K. L. Jensen, E. A. Standley, T. F. Jamison, J. Am. Chem. Soc., 2014, 136, 11145-11152.
A radical alkylation of aldimines and ketimines with 4-alkyl-1,4-dihydropyridines in very good yields is cocatalyzed by either an iridium or a ruthenium complex and a Brønsted acid under visible light irradiation. Common functional groups, such as hydroxyl groups, ester, amide, ether, cyanide, and heterocycles, are tolerated.
H.-H. Zhang, S. Yu, J. Org. Chem., 2017, 82, 9995-10006.
A mixed 2-pyridonate-Ta(NMe2)3Cl complex catalyzes a direct C-H alkylation adjacent to nitrogen in unprotected secondary amines. The hydroaminoalkylation of sterically demanding internal alkenes to yield α-alkylated amines provides a direct, atom-economic formation of C(sp3)-C(sp3) bonds.
E. Chong, J. W. Brandt, L. L. Schafer, J. Am. Chem. Soc., 2014, 136, 10898-10901.
A mild, versatile, copper-catalyzed three-component coupling of organoindium reagents with imines and acid chlorides provides α-substituted amides or N-protected amines in a single step with the sole byproduct being indium trichloride.
D. A. Black, B. A. Arndtsen, Org. Lett., 2006, 8, 1991-1993.
Trialkylalanes undergo addition to imines in the presence of a catalytic amount of dichlorodicyclopentadienylzirconium(IV). The reaction tolerates the presence of various functional groups. A possible reaction pathway is discussed.
C. Denhez, J.-L. Vasse, J. Szymoniak, Synthesis, 2005, 2075-2079.
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 copper-catalyzed Petasis-type reaction of imines, acid chlorides, and organoboranes gives α-substituted amides. This reaction does not require the use of activated imines or the transfer of special units from the organoboranes and represent a useful generalization of the Petasis reaction.
M. S. T. Morin, Y. Lu, D. A. Black, B. A. Arndtsen, J. Org. Chem., 2012, 77, 2013-2017.
β-Functionalized sulfonamides were produced in good yields by the regioselective ring opening of N-tosylaziridines with trimethylsilylated nucleophiles, catalyzed by N,N,N',N'-tetramethylethylenediamine (TMEDA).
S. Minakata, Y. Okada, Y. Oderaotoshi, M. Komatsu, Org. Lett., 2005, 7, 3509-3512.
The efficiency of the photoinduced radical addition of tertiary amines to olefinic double bonds is significantly enhanced and the stereoselectivity is influenced when thiocarbonyl compounds are added to the reaction mixture.
D. Harakat, J. Pesch, S. Marinkovic, N. Hoffmann, Org. Biomol. Chem., 2006, 4, 1202-1205.
Reaction of N-(2-chloroethylidene)-tert-butylsulfinamide with Grignard reagents or organoceriums gives terminal N-tert-butylsulfinyl aziridines in good yields and with organoceriums good diastereomeric ratios. Oxidation of terminal N-tert-butylsulfinyl aziridines provides synthetically useful terminal N-Bus (Bus = tert-butylsulfonyl) aziridines.
D. M. Hodgson, J. Kloesges, B. Evans, Synthesis, 2009, 1923-1932.