[Bakterien]

I have a molecule with an ester and a tertiary amide. My aim is to reduce only the ester to an alcohol, keeping the amide intact. NaBH4 seems to be to weak and LiAlH4 is to strong and will reduce both groups. In Clayden they mentioned LiBH4. Is it selective ? Any experiences ?

[Babcock_Hall]

Do you have a choice about the identity of the ester?

[Bakterien]

Not sure what you mean. The ester is a terminal ester with a methoxide group attached to a carbonyl.

[Babcock_Hall]

In effect my question was whether you have to have a methyl ester or could you tolerate a different ester, possibly phenyl for example.  I am not sure about LiBH₄.

[rolnor]

I would try LiBH4, it could work, maby in t-BuOH. Or diisobutylaluminiumhydride at -78°C.

[kriggy]

NaBH4 worked nice for me with MeOH in the mixture.
http://www.arkat-usa.org/get-file/23589/

If you try it, I suggest use of excessively large glassware because it foams a lot during MeOH addition

[zarhym]

I would try hydrolysis the ester with LiOH, then reduce the carboxylic acid with BH3Me2S.
Tertiary amide should be very stable in these two steps.

[lioner3058]

The safest method is to protect the amino group, then convert the ester to an alcohol, and then remove the Conservation groups of amino.

[clarkstill]

Yes, LiBH4 is selective: https://pubs.acs.org/doi/abs/10.1021/jo00371a017