Categories: C-N Bond Formation > Amines >
Synthesis of benzylic amines
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Recent Literature
A protocol for the dehydrative amination of alcohols in water using a
water-soluble calix[4]resorcinarene sulfonic acid as a reusable multifunctional
catalyst allows an environmentally benign synthesis of benzylic and allylic
amines. The aqueous phase containing the catalyst can be readily recycled.
S. Shirakawa, S. Shimizu, Synlett, 2008,
1539-1542.
Benzylic hydrocarbons are selectively converted to the corresponding
sulfonamides by the [Cu(CH3CN)4]PF6-catalyzed reaction with anhydrous
TolSO2NNaCl (chloramine-T). Under the same conditions, representative ethers
and olefins are
also amidated.
R. Bhuyan, K. M. Nicholas, Org. Lett., 2007,
9, 3957-3959.
A palladium complex generated in situ from [Pd(η3-C3H5)(cod)]BF4
and DPPF is a good catalyst for benzylations of malonates with a wide range
of benzyl methyl carbonates. The DPEphos ligand is superior to DPPF in the
case of palladium-catalyzed benzylic amination of benzylic esters.
R. Kuwano, Y. Kondo, Y. Matuyama, J. Am. Chem. Soc.,
2003,
125, 12104-12105.
Treatment of ketones with
ammonia in ethanol and titanium(IV) isopropoxide, followed by in situ reduction
with sodium borohydride allows a highly chemoselective reductive
mono-alkylation of ammonia. A simple workup afforded primary amines in good to
excellent yields. Reductive alkylation of ammonia with aldehydes afforded the corresponding symmetrical secondary amines selectively.
B. Miriyala, S. Bhattacharyya, J. S. Williamson, Tetrahedron, 2004,
60, 1463-1471.
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.
. Cote, A. B. Charette, J. Org. Chem.,
2005,
70, 10864-10867.
Nickel nanoparticles catalyse the reductive amination of aldehydes by transfer
hydrogenation with isopropanol at 76°C.
F. Alonso, P. Riente, M. Yus, Synlett, 2008, 1289-1292.
Manganese dioxide is employed as an in situ oxidant for the one-pot conversion
of alcohols into imines. In combination with polymer-supported cyanoborohydride
(PSCBH), a one-pot oxidation-imine formation-reduction sequence enables alcohols
to be converted directly into both secondary and tertiary amines.
L. Blackburn, R. J. K. Taylor, Org.
Lett., 2001, 3, 1637-1639.
The regioselective opening of Bn2N-α-methylserine-β-lactone
with organocuprates gave enantiopure α-methyl amino acids in excellent yields.
N. D. Smith, A. M. Wohlrab, M. Goodman, Org. Lett., 2005,
7, 255-258.
A wide range of chiral propargylamines can be prepared in a one-pot
three-component reaction between an alkyne, an aldehyde and a secondary
amine at room temperature in the presence of CuBr and (R)-quinap in
good yield and good enantioselectivity.
N. Gommermann, C. Koradin, K. Polborn, P. Knochel, Angew. Chem., 2003,
115, 5941-5944.
