Cellphone Charger Electrochemistry

I'm frankly amazed at chemists' rugged pragmatism. Our ilk often repurpose seemingly innocent household items - floodlights, LED strips, paraffin wax - adapting them for making new molecules in interesting ways. Have a peek at this new paper, which appeared* last week in Angewandte Chemie. 

The Aubé group, recently of UNC, wondered whether expensive setups from scientific vendors were potential roadblocks to wide adoption of electrochemistry. Their ideal recipe called for a direct current (DC) source capable of removing two electrons and an H from a lactam to generate an N-acyliminium ion. Looking around, the researchers realized that today's ubiquitous cellphone chargers might just do the trick. Shave back some wires, attach some copper clamps, and presto! Cheap, effective electrochemistry.**

Using their DIY e-chem setup, the Aubé group traps a wide variety of stereochemically-rich acyliminiums as the corresponding methanol adducts (19-93% yields). Now the real fun starts: there's a whole bunch of interesting arylations and other additions to these species one can access using off-the-shelf Lewis acids like titanium tetrachloride or boron trifluoride:

Adapted from Aube, Angewandte Chemie, 2015 ASAP

I'll be excited to see small libraries of diversified products emerge from this work. However, a "one-pot" functionalization - electrochemistry with the desired nucleophile already present - still seems a distant dream.

Hopefully, the apparent ease of operation of "cellphone charger e-chem" prompts other groups to give it a try. If your group dips their toes into this field, please drop me a line in the comments section.

--
*Thanks to Professor Brandon Findlay (@Chemtips) for pointing out this paper!

**I'm tickled pink at how many organic synthesis papers these days include photographic records of reaction setups. I'd like to believe that Blog Syn played a small role in advancing this change.

Golden Bacteria?

An amazing breakthrough (!) recently made the rounds on Wired and Gizmodo: a synthetic chemistry / art-house installation in which microbes "...turn liquid gold into 24-karat gold." Two professors from Michigan State University - a microbiologist and a science artist - teamed up to produce the exhibit, entitled "The Great Work of the Metal Lover," which is currently on display at an Austrian art competition.

Credit: G.L. Kohuth | MSU

Hold your applause - the science doesn't travel well across multiple media outlets. The bacterium in question, Cupriavidus metallidurans, reduces gold(III) chloride solution (likely HAuCl4) and precipitates out pure metallic gold. C. metallidurans actually does have some 'super powers' - the last decade (PubMed) shows similar successes with copper, mercury, and lead. Heck, it's even been shot into space! 

But the MSU press release may win the hyperbole 'gold medal.' Here's a few choice lines:

"Cupriavidus metallidurans can grow on massive concentrations of gold chloride – or liquid gold, a toxic chemical compound found in nature"

Gold chloride, liquid gold? Oh, you mean the solid gold salt? With almost no tox data on the MSDS?  

"[the installation] uses a combination of biotechnology, art and alchemy to turn liquid gold into 24-karat gold"

Ye Gods. No alchemy here! I'm not a biochemist - just a #KnuckleDraggingOrganiker - but I'd guess there's a perfectly reasonable, well-studied reduction mechanism operating. Can I get a reductase over here? (P.S. the only "liquid gold" I know of is molten gold)

“This is neo-alchemy. Every part, every detail of the project is a cross between modern microbiology and alchemy"

No comment (see above). 

"...the researchers’ success in creating gold raises questions about greed, economy and environmental impact, focusing on the ethics related to science and the engineering of nature"

Unless we're talking phlogiston and aether here, there's no "creation" of gold: it's a reduction. And utilizing a bacterium to do what it likes to do anyway hardly sets up an ethical or social inquiry.

"[this work]...speaks directly to the scientific preoccupation while trying to shape and bend biology to our will within the postbiological age"  

I really don't understand what they're trying to say here. (Perhaps I need to read Art for Dummies...)

OK, scientific criticism aside, the work looks pretty neat. How often do you get to see electrochemistry in an art exhibit? In the end, I guess the ends justify the means - if just a few people look at it, and think "I wonder how that works?" it will have served its purpose.