[Kaladiscope]

Hi people,

I want to elongate the side chain for one specific amino acid, specifically for Fmoc-Lysine-OH. I want to add a new methylene, so I want to remove the amino group and put a methylene. I don't know if it is better to start with the corresponding 6 hydroxonorleucine, which have an hydroxyl group instead of amine group. So in other words, what I wanted to do is the following thing:



Do u know any chemichal reaction to do that? I was just thinking in doing the hydroxyl a better leaving group, for example making the tosylate or mesylate. But then I don't know how to attach for example a ^-CH₂-OH.

Thanks,

[discodermolide]

Looks like you will have to make an ester, something like benzhydryl. Remove the NH by putting a Boc on it. Oxidise the alcohol to the aldehyde then Wittig to put in the one C atom, then hydroborate the C=C to get your target after deprotection.