A very accomplished organic chemist has died. Albert Jakob Eschenmoser, 97, retired professor of chemistry at ETH, Zurich (the Swiss Federal Institute of Technology) and The Skaggs Institute for Chemical Biology at The Scripps Research Institute in La Jolla, California. ETH Zurich is regarded as one of the best universities in the world. It is focused primarily on science, technology, engineering, and mathematics.

Eschenmoser is perhaps best known for his work on the synthesis of vitamin B12 along with Robert B. Woodward of Harvard University. Between the two groups this synthesis was accomplished over many years and required the labor of more than 100 students and postdocs grinding through their short times in the lab. This landmark synthesis was published in 1973.

This was perhaps the most complex organic synthesis of the time in 1973. Note that the wedge lines are meant to indicate that the feature is coming up out of the page and the dashed lines are jutting behind the page. Natural B12 has only 1 configuration of chemical bonds. Swapping something with a wedge with a dashed line group produces a different substance called a diastereomer. This all by itself makes the synthesis of B12 very difficult. Not only do the atoms have to be connected properly, but their arrangement in space must be correct also. This is called stereochemistry.