Amides are pretty tough to reduce down to their corresponding amines. Typically, you hydrogenate at high temperature and pressure or use LAH, borane, dissolving metals and stuff like that, under – obviously – pretty harsh conditions. Good old March (5th ed., ISBN: 0471585890) says: “The reaction is more difficult than the reduction of most other functional groups, and other groups can be reduced without disturbing an amide function.” In other words, amides are among the last functional groups that surrender to hydrides.
A colleague of mine tipped me about this paper by Beller et al., which turns everything we know about amide reduction upside down. It’s just amazing!
JACS 2010, 132, 1770-1771. (DOI: 10.1021/ja910083q)
Check it out! Using this protocol, you can selectively reduce amides in the presence of esters, ethers, nitro groups, nitriles, azo functionalities, non-conjugated and conjugated double bonds and – drum roll – even ketones.
As far as I can tell, the limitation seems to be that the amide has to be tertiary. But what about mono- or di-allyl amides then? Would they work? Mono- and di-allyl amines are straightforwardly converted to primary amines under mild conditions, using for instance Pd(PPh3)4 and N,N-dimethylbarbituric acid (JOC 1993, 58, 6109-6113., DOI: 10.1021/jo00074a044).
My two cents.
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