Archive for January, 2014

3D-rendered molecular models on this blog: an update.

Thursday, January 16th, 2014

So much to do, so little time to do it. That is my excuse at least. Right from my first post on this blog in 2008 I have tried to enhance it using Jmol, a Java-based applet (normally indicated with the caption Click for 3D). This has been pretty stable for some five years now, but a recent spate of security-based releases of the JRE (Java runtime environment) for desktop computers has impacted, the latest of which was released yesterday (Java 7, V 51).  Put simply, when I started, an unsigned applet was fine. Now to run, it can only be a properly signed applet. Fortunately, there are two solutions:

(more…)

Three-for-one: a pericyclic brain teaser.

Sunday, January 12th, 2014

A game one can play with pericyclic reactions is to ask students to identify what type a given example is. So take for example the reaction below.

(more…)

A simple pericyclic reaction encapsulating the four thermal selection rules.

Thursday, January 2nd, 2014

As my previous post hints, I am performing my annual spring-clean of lecture notes on pericyclic reactions. Such reactions, and their stereochemistry, are described by a set of selection rules. I am always on the lookout for a simple example which can most concisely summarise these rules. The (hypothetical) one shown below I think nicely achieves this, and raises some interesting issues in the process.14vs12

(more…)