Categories: C-H Bond Formation >
Reduction of amides to imines
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 transition-metal-free catalytic hydrosilylation based on t-BuOK (5 mol %) and (MeO)3SiH or (EtO)3SiH allows the reduction of tertiary amides to their corresponding enamines with high selectivity in very good yields.
A. Volkov, F. Tinnis, H. Adolfsson, Org. Lett., 2014, 16, 680-683.