Categories: C-H Bond Formation >
Reduction of amides to amines
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Recent Literature
1,1,3,3-tetramethyldisiloxane and 1,2-bis(dimethylsilyl)benzene are found to be
effective reducing agents for a platinum-catalyzed reduction of carboxamides to
amines. The reaction tolerates other reducible functional groups such as NO2,
CO2R, CN, C═C, Cl, and Br. The product is obtained by simple
extraction.
S. Hanada, E. Tsutsumi, Y. Motoyama, H. Nagashima, J. Am. Chem. Soc., 2009,
131, 15032-15040.
A zinc-catalyzed reduction of tertiary amides shows remarkable chemoselectivity
and substrate scope tolerating ester, ether, nitro, cyano, azo, and keto
substituents.
S. Das, D. Addis, S. Zhou, K. Junge, M. Beller, J. Am. Chem. Soc., 2010,
132, 1770-1771.
An expeditious and practical method for the reduction of various amides and
lactams to amines in good to excellent yields is consisted of activation with Tf2O
followed by reduction with sodium borohydride in THF at room temperature. This
method offers TBDPS-group tolerance, short reaction time, and a simple workup.
S.-H. Xiang, J. Xu, H.-Q. Yuan, P.-Q. Huang, Synlett, 2010,
1829-1832.
A chemoselective activation of a secondary amide with triflic anhydride in the
presence of 2-fluoropyridine enables a mild reduction using triethylsilane, a
cheap and rather inert reagent. Imines can be isolated after a basic workup or
readily transformed to the aldehydes following an acidic workup. The amine
moiety can be accessed by addition of Hantzsch ester to the reaction mixture.
G. Pelletier, W. S. Bechara, A. B. Charette, J. Am. Chem. Soc., 2010,
132, 12817-12819.
A triruthenium cluster catalyzes the reaction of secondary amides with
hydrosilanes, yielding a mixture of secondary amines, tertiary amines, and silyl
enamines. Production of secondary amines with complete selectivity is achieved
by the use of higher concentration of the catalyst and bifunctional hydrosilanes
such as 1,1,3,3-tetramethyldisiloxane followed by acidic workup.
S. Hanada, T. Ishida, Y. Motoyama, H. Nagashima, J. Org. Chem.,
2007,
72, 7551-7559.
Phenol carbamates undergo an anionic ortho-Fries rearrangement to
their corresponding amides in the presence of LDA. Sterically hindered
substrates can be converted with s-BuLi/TMEDA at -90°C. The amides can be efficiently reduced with lithium aluminum hydride
to the corresponding Mannich bases.
N. Assimomytis, Y. Sariyannis, G. Stavropoulos, P. G. Tsoungas, G. Varvounis, P.
Cordopatis, Synlett, 2009,
2777-2782.
Odorless Dod-S-Me and MMS are developed as efficient borane carriers. The
yields of hydroborations and reductions with the borane complex of Dod-S-Me
are very high. The recovery of Dod-S-Me after the reaction is quantitative.
P. K. Patra, K. Nishide, K. Fuji, M. Node, Synthesis, 2004,
1003-1006.
