A pinch of eye of newt, no ? How about water extract of banana ? For a Suzuki-Miyaura reaction ?

Hi everyone, I know it has been a while since I posted.  I am back.

I recently, made it back onto the campus of my alma mater to check what was happening in the world of chemistry.  To introduce the lastest batch of interesting papers, I thought I would select something a little short, with a little bit of levity to it.

I don’t mean to poke fun at this journal article, but how did they ever think of this ?  There is quite a lot of interest in approaching chemistry with green principles in mind.  Let’s face it.  A few decades ago, I am sure no one was thinking of converting straw (insert any other cellulosic feedstock) into ethanol.  Due to geographic location, some feedstocks are more prevalent than others.  Taking a waste product such as banana peel and reusing it in a reaction is pretty novel.

Consider the following article, “A novel green protocol for ligand free Suzuki–Miyaura cross-coupling reactions in WEB at room temperature”, by Preeti Rekha Boruah, Abdul Aziz Ali, Bishwajit Saikia* and Diganta Sarma, Green Chemistry, DOI: 10.1039/c4gc02522a.  I should mention that the acronym for WEB stands for water extract of banana.

It turns out not to be that crazy a notion, that WEB might be useful.  Check out this article that I found on the web, click here for an article on the ash content of banana.

Who knew that the water extract of banana ash was quite basic, pH 11 ?  5 grams of ash to 100 ml of water and the reaction was ran at room temperature.  No needed base or phosphine.  That’s pretty nice.  I will throw some reactions so you can take a look at the variety of substrates.  I should mention that banana peel was used, no edible foodstuff.

I think I would love to try that out.  Let me show some results, so you can have an appreciation for this work.

Suzuki-Miyaura coupling with WEB

Suzuki-Miyaura coupling with WEB

The palladium load is 0.5 %, with 1 eq. of aryl bromide, 1.2 eq of boronic acid, in 3 mL WEB.  Yields are isolated, presumably after column chromatography.  I was hoping that the product just crashed out of solution but it was extracted out with diethyl ether.  I would have liked to see no solvent use there, but we can’t always have everything.  I hadn’t heard of water extract of banana before, so I definitely learned something there.  Interesting solvent and application for the Suzuki.  The role of the solvent is not well understood, but given the high basicity, its role as base could be surmised.  These are small aryl molecule couplings.   I wonder if it would work as well with larger molecules with poor water solubility.  Who is to say.  Stay tuned, I have a paper on an interesting crystallization coming up.

Feel free to follow me on Twitter, LinkedIn, Google+ and if you have any comments, suggestions, you can reach me at developtheprocess@gmail.com.  It is always nice to hear from colleagues.

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2 thoughts on “A pinch of eye of newt, no ? How about water extract of banana ? For a Suzuki-Miyaura reaction ?

  1. Looks interesting, but not exactly about to be snapped up in development labs! However, the reactions are very quick given the palladium load and absence of a fancy ligand. Would have been nice to see an investigation of the nature of the catalyst – maybe there´s something in WEB that forms fantastic nanoparticles, for instance, and these catalyse the process. If so, WEB could have more applications in nanoparticle synthesis than in Suzukis themselves.

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    • Great comment. This might serve more as a novel reaction, not necessarily for development. There is a certain
      amount of drying of the banana peel, which may be accelerated. I was thinking that this is very geographically
      dependent as well. They may have the stockpiles of banana peel from which to draw.

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