Thursday, March 31, 2011

Danishefsky Cyclobutenone in Diels-Alder Reaction

JACS 2010, 11004

Diels-Alder has been a beautiful and powerful cycloadition reaction for many masters such as Woodward. It is an atom-efficient, 4+2, environment-insensitive ring-formation reaction and fits click chemistry concept in many aspects . 

Danishefsky's work expanded its scope by using cyclobutenone as a highly reactive dienophile. The strained cyclobutanone in the Diels-Alder product undergoes regioselective ring-expansion to give cyclopentanone, lactam, lactone. As an example indicated in the graph, the approach provides a variety of structures not accesible via direct Diels-Alder reaction.      

Sunday, March 6, 2011

Shapless video of applied click chemistry

NIST Colloquium Series: Applied Click Chemistry: From Dyeing Cotton to Drug Discovery

Click the link above and listen to (and watch) click chemistry described by K Barry Sharpless himself!

He gave the speech at the NIST Colloquium, December 15, 2006. In almost 1.5 hours he described click chemistry as a molecular approach that uses the most practical or reliable chemical transformations in a variety of applications.