I want to couple the amino acid with Alkyl chains by Decarboxylation of amino acids.
my questions are
1. can we remove the carboxylic acid group having Pka ranging from 3-4.5
2. how to prevent the Alaninate and ester formation which are the major side product.
3. can we carry out Decarboxylation in pure water as solvent
4. can we get the Decarboxylated product at room temperature using photocatalyst (and which kind of photocatalyst would be best)
5. how can we inhibits the byproduct formations i-e ester formation?
1) there is a general summary of decarboxylation methods
http://www.organic-chemistry.org/synthesis/C1H/decarboxylations.shtm
this paper looks to be most applicable
Photocatalytic Decarboxylative Reduction of Carboxylic Acids and Its Application in Asymmetric Synthesis
Carlo Cassani, Giulia Bergonzini, and Carl-Johan Wallentin
Org. Lett., 2014, 16 (16), pp 4228–4231
2) this really depends on how you are doing the reaction sequence. But in the paper above it looks like the amine needs to be protected first before the decarboxylation.
3) Mechanistically, water and protic solvents are usually difficult to use for these type of reactions
This is a fairly new paper in very high end journal which could allow you to couple a carboxylic acid and an alkyl halide together by decarboxylating the carboxylic acid into an alkyl radical. The reaction requires Blue LED light (we bought ours from Amazon), an Iridium photocatalyst, and a Nickel cross coupling catalyst.
They actually use a lot of amino acids in their substrate scope so I think this would be very helpful to you.
https://www.nature.com/articles/nature19056?WT.ec_id=NATURE-20160818&spMailingID=52085095&spUserID=MjA1NzcwMjE4MQS2&spJobID=983154956&spReportId=OTgzMTU0OTU2S0
Respected Eugene & Greg.
I had already tried those mechanism but every time i end up with ester, secondly instead of secondary carboxylic acid i am interested in decarboxylation of primary carboxylic acid.
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