Previously, a mechanism with a reasonable predicted energy was modelled for the isomerisation of an oxetane carboxylic acid to a lactone by using two further molecules of acid to transfer the proton and in the process encouraging an Sn2 reaction with inversion to open the oxetane ring. We are now ready to explore variations to this mechanism to see what happens.

In 2006[cite]10.1021/ic0519988[/cite] we published an article illustrating various types of pseudorotations in small molecules. It’s been cited 20 times since then, so reasonable interest! We described rotations known as Lever and Turnstile as well as the better known Berry mode. Because the differences between these rotations are quite subtle, we included an interactive electronic supporting information to illustrate them.

In the previous post, I looked at the intramolecular rearrangement of the oxetane carboxylic acid to a lactone, finding the barrier to the Sn2 reaction with retention was unfeasibly high. Here I explore alternatives. This first attempt uses a second molecule of a carboxylic acid (modelled as formic acid for simplicity) to see if it can catalyse the reaction.

The growing accessibility of computational chemistry has, unfortunately, led to a preponderance of papers with bad computations.

Derek Lowe’s blog has a recent post entitled A Downside to Oxetane Acids which picks up on a recent article[cite]10.1021/acs.orglett.2c01402[/cite] describing how these acids are unexpectedly unstable, isomerising to a lactone at a significant rate without the apparent need for any catalyst. This is important because these types of compound occur frequently in the medicinal chemistry literature.

This is the first in what will hopefully become a series of blog posts focusing on the fascinating work of Dan Singleton (professor at Texas A&M). My goal is to provide concise and accessible summaries of his work and highlight conclusions relevant to the mechanistic or computational chemist. A central theme in mechanistic chemistry is the question of concertedness: if two steps occur simultaneously (“concerted”) or one occurs

As an undergraduate student in the sciences at MIT, contempt for management consulting was commonplace. Consulting was the path for people who had ambition devoid of any real interests, the “sellout road” where you made endless Powerpoints instead of providing any tangible improvement to the world. In contrast, going to graduate school was a choice that showed commitment and integrity.

For many organic chemists, it’s hard to grasp the vast difference between various “fast” units of time. For instance, if a reactive intermediate has a lifetime of microseconds, does that mean it can escape the solvent shell and react with a substrate? What about a lifetime of nanoseconds, picoseconds, or femtoseconds?

WATOC 2020 was just held in 2022 in Vancouver Canada, over one week. With many lectures held in parallel, it is not possible for one person to cover anything like the topics presented, so this is a personal view of some of those talks that I attended. As happens with many such events, common themes gradually emerge and here I highlight just two that struck me as important for the future of computational chemistry. Dispersion .

While IR spectroscopy is still taught in introductory organic chemistry classes, it has been almost completely replaced by NMR spectroscopy and mass spectrometry for routine structural assignments.