In the previous post, I investigated the mechanism of cyclopropanation of an enal using a benzylic chloride using a quantum chemistry based procedure. Here I take a look at the NMR spectra of the resulting cyclopropane products, with an evaluation of the original stereochemical assignments.[cite]10.1021/acs.jchemed.7b00566[/cite] Three products were identified, 4a-c (aryl=2,4-dinitro) with a fourth diastereomer undetected.
Symbiosis between computation and experiment is increasingly evident in pedagogic journals such as J. Chemical Education . Thus an example of original laboratory experiments[cite]10.1021/ed077p271[/cite],[cite]10.1021/ed078p1266[/cite] that later became twinned with a computational counterpart.[cite]10.1021/ed500398e[/cite] So when I spotted this recent lab experiment[cite]10.1021/acs.jchemed.7b00566[/cite] I felt another twinning
Following the general recognition of carbon as being tetrahedrally tetravalent in 1869 (Paterno) and 1874 (Van’t Hoff and Le Bell), an early seminal exploitation of this to the conformation of cyclohexane was by Hermann Sachse in 1890.[cite]10.1002/cber.189002301216 [/cite] This was verified when the Braggs in 1913[cite]10.1098/rspa.1913.0084[/cite], followed by an oft-cited article by Mohr in 1918,[cite]10.1002/prac.19180980123[/cite]
In 2012, I wrote a story of the first ever reaction curly arrows, attributed to Robert Robinson in 1924. At the time there was a great rivalry between him and another UK chemist, Christopher Ingold, with the latter also asserting his claim for their use.
White City is a small area in west london created as an exhibition site in 1908, morphing over the years into an Olympic games venue, a greyhound track, the home nearby of the BBC (British Broadcasting Corporation) and most recently the new western campus for Imperial College London. ♣ The first Imperial department to move into the MSRH (Molecular Sciences Research Hub) building is chemistry.
Harnessing FAIR data is an event being held in London on September 3rd; no doubt all the speakers will espouse its virtues and speculate about how to realize its potential. ♥ Admirable aspirations indeed. Capturing hearts and minds also needs lots of real life applications!
FAIR is one of those acronyms that spreads rapidly, acquires a life of its own and can mean many things to different groups. A two-day event has just been held in Amsterdam to bring some of those groups from the chemical sciences together to better understand FAIR. Here I note a few items that caught my attention. Fairsharing.org was the basis for several presentations.
This last month, as a follow-up to the preceding post on the colour of flowers, I have been moonlighting by blogging elsewhere. Do go visit my “guerrilla blog” at perivalepark.london. Part of this project involves visiting two “physic or botanic” gardens, which originate from early 17th century explorations of herbs and other botanicals as medicines. Both are very old and their chemistry is indeed fascinating; more of which later.
It was about a year ago that I came across a profusion of colour in my local Park. Although colour in fact was the topic that sparked my interest in chemistry many years ago (the fantastic reds produced by diazocoupling reactions), I had never really tracked down the origin of colours in many flowers. It is of course a vast field.
