Categories: N-H Bond Formation >
Cleavage of C-N bonds
Recent Literature
A synergistic catalytic system based on Pd-C in the presence of
1,1,2-trichloroethane enabled the N-debenzylation of benzylamines to
yield crystal amine hydrochlorides in practically quantitative yields.
C. Cheng, J. Sun, L. Xing, J. Xu, X. Wang, Y. Hu, J. Org. Chem., 2009,
74, 5671-5674.
Grubbs' carbene catalyzes a deprotection of allylic amines via a
nitrogen-assisted ruthenium-catalyzed isomerization, followed by hydrolysis of
the enamine intermediate.
B. Alcaide, P. Almendros, J. M. Alonso, M. F. Aly, Org. Lett., 2001, 3,
3781-3784.
Optically pure C2-symmetrical cyclic amines were
efficiently synthesized from the corresponding diols obtained from an
enantioselective borohydride reduction of diketones in the presence of a chiral
β-ketoiminato cobalt(II) catalyst.
M. Sato, Y. Gunji, T. Ikeno, T. Yamada, Synthesis, 2004,
1434-1438.
A new one-pot method is described for the removal of
O- and N-allyl protecting groups under oxidative conditions at near
neutral pH. The allyl group undergoes hydroxylation and subsequent periodate
scission of the vicinal diol. Repetition of this reaction sequence on the enol
tautomer of the aldehyde intermediate releases the deprotected functional group.
P. I. Kitov, D. R. Bundle, Org. Lett., 2001, 3,
2835-2838.
Deprotection of allyl ethers, amines and esters to
liberate hydroxyl, amino and acid groups is achieved under mild conditions. The
reagent combination employed for this transformation is polymethylhydrosiloxane
(PMHS), ZnCl2 and Pd(PPh3)4.
S. Chandrasekhar, R. Reddy, R. J. Rao, Tetrahedron, 2001, 57,
3435-3438.
The homoallyl moiety (hAllyl) can be used as a general protecting group for
several functionalities. It can be chemoselectively removed via a sequential,
one-pot cross-metathesis/elimination sequence.
B. H. Lipshutz, S. Ghorai, W. W. Y. Leong, J. Org. Chem., 2009,
74, 2854-2857.
The reaction of aliphatic and aromatic secondary and tertiary N-tritylamines
with lithium powder and a catalytic amount of naphthalene led to reductive
detritylation affording the corresponding amines in good yields. The trityl
group could selectively be removed in the presence of an allyl or a benzyl
group.
C. Behloul, D. Guijarro, M. Yus, Synthesis, 2004, 1274-1280.
A totally regioselective transformation of aromatic N-4-methoxyphenylaziridine
2-carboxamides into 2-aminoamides is promoted by active manganese (Mn*). α-Amino
ketones can be readily obtained by reaction of morpholine-derived 2-aminoamides
with organolithium compounds.
J. M. Concellón, H. Rodríguez-Solla, V. del Amo, P. Díaz, J. Org. Chem., 2010,
75, 2407-2410.
Palladium and Raney nickel catalyze the methanolysis of strongly complexed
borane-amine adducts. The method is applicable to primary, secondary, tertiary,
and aromatic amines, and the mildness of the reaction conditions allows
preservation of otherwise labile functional groups.
M. Couturier, J. L. Tucker, B. M. Andresen, P. Dube, J. T. Negri, Org.
Lett., 2001, 3, 465-467.
A highly enantioselective, catalytic three-component coupling of aldehydes,
alkynes, and 4-piperidone hydrochloride hydrate affords the corresponding
tertiary propargylamines in useful yields. A selective cleavage of the
piperidone protecting group is possible using either ammonia/EtOH or a
polymer-supported scavenger amine.
P. Aschwanden, C. R. J. Stephenson, E. M. Carreira, Org. Lett.,
2006, 8, 2437-2440.
The bifunctional ferrocene FcCH2CO2H, with electron donor
and acceptor moieties in the same molecule, has been shown to be advantageous
for use as a catalyst in the N-demethylation of a number of tertiary N-methylamines
such as codeine, thebaine, and oripavine. These substrates are readily
N-demethylated under mild conditions, employing sub-stoichiometric amounts of
the substituted ferrocene at ambient temperature.
G. B. Kok, P. J. Scammels, Synthesis, 2012, 44,
2587-2594.
A catalytic amount of tetrasodium
5,10,15,20-tetra(4-sulfophenyl)porphyrinatoiron(II) effected N-demethylation of
N-oxide analogues of opiates to the corresponding N-nor semisynthetic opiate
pharmaceuticals in excellent yields. The catalyst was readily removed and
recycled.
Z. Dong, P. J. Scammels, J. Org. Chem., 2007,
72, 9881-9885.
A general and efficient method enables the synthesis of tertiary amides from
readily available tertiary amines and anhydrides in the presence of FeCl2
as catalyst and tert-butyl hydroperoxide in water (T-Hydro) as oxidant.
Mechanistic studies indicated that the in situ-generated α-amino peroxide of
tertiary amine and iminium ion act as key intermediates.
Y. Li, L. Ma, F. Jia, Z. Li, J. Org. Chem., 2013,
78, 5638-5646.
Demethylation of N,N-dimethylanilines was carried out in various ionic
liquids and acetonitrile as well as under solvent-free conditions. The
reactivity dramatically depends on the employed solvent, with [bmim]Cl showing
the best reactivity.
S. Imoria, H. Togo, Synlett, 2006,
2629-2632.
Cp*Ir complexes bearing a chiral N-(2-picolyl)sulfonamidato catalyze a
convenient asymmetric reductive amination of benzylic ketones using readily
available β-amino alcohols as chiral aminating agents. The amino alcohol-derived
chiral auxiliary was easily removed by mild periodic oxidants, leading to
optically active primary β-arylamines without erosion of the optical purity.
T. Kawada, K. Yabushita, T. Yasuda, T. Ohta, T. Yajima, K. Tanaka, N. Utsumi, M.
Watanabe, K. Murata, Y. Kayaki, S. Kuwata, T. Katayama, J. Org. Chem., 2022, 87,
8458-8468.