[YuliaSnow]

Can someone explain the mechanism of reductive amination of an imine to an amine using H2/Pt and NaBH4? I can't find details of how it works anywhere.

http://www.wikipremed.com/03_organicmechanisms.php?mch_code=030208_080

Also, in the last step of the rxn in the link where it goes from the imine -H2-> amine, why doesn't the N atom get a H and instead gets lone pairs? I'm confused about this because alkenes + H2 gives an alkane and both carbons have H where as in this case, the carbon gets a H but the nitrogen gets lone pairs.

Thanks

[kriggy]

It does get hydrogen atom, in the imine it is =NH while in the amine -NH₂. Its confusing because the lone pair is drawn in the imine but not int he final product

[zarhym]

http://www.organic-chemistry.org/abstracts/literature/717.shtm

If you are doing a reaction, try this first. If you are just wondering about the mechanism, read the paper.