Torsion

I’ve been reading a book called “Napoleon’s Buttons” by Penny LeCouteur and Jay Burreson. The subtitle is “17 Molecules That Changed History.” One of those molecules is isoprene, which is one of my favorite compounds, mainly because I am fascinated by the myriad ways in which it reacts to form … Read more

More Spectra

For years the NIST Google button has offered Molecula users access to IR and MS data for the roughly 40,000 compounds in the NIST Chemistry WebBook. Now the recently added SDBS Google button provides users with access to 13C, 1H, IR, ESR, Raman, and MS data for thousands of organic … Read more

Stereochemistry III-Diastereomers

For a molecule that contains one chiral carbon atom there are two possible stereoisomers. They are called enantiomers. For molecules that contain n chiral carbon atoms 2n defines the maximum number of stereoisomers that are possible. Consider 3-chlorobutan-2-ol. Both C-2 and C-3 are chiral, so there are 2… Read more

Stereochemistry I-Chirality

In 1848 Louis Pasteur isolated crystals of sodium ammonium tartrate from the dregs of wine barrels. He noted that there were two types of crystals, which appeared to be mirror images of each other. He was able to separate these by hand. Solutions of the separated crystals rotated plane polarized … Read more

Diels Alder Reaction

The Diels-Alder reaction was first reported by Diels and Alder in 1928. The first use of this reaction in a total synthesis was not reported until 1952 (Woodward synthesis of cholesterol) – two years after the Nobel Prize was awarded to Diels and Alder. The original discovery by … Read more