An Alkene Zipper Reaction

Aaron over at Carbon Based Curiosities has recently posted about one of my favorite reactions, the alkene zipper reaction catalyzed by 1,3-diaminopropane and potassium hydride. Most of the time this reaction works great, but it is thermodynamic and has some problems when your alkyne is stabilized by conjugation. Anyway, an interesting paper appeared on the JACS ASAP web site last week dealing with the alkene version of a zipper reaction. It is a very nice contribution from Doug Grotjahn and co-workers from San Diego State University. It utilizes a bifunctional ruthenium catalyst to walk an alkene down the chain until it reaches an alcohol. Once an enol is generated it quickly tautomerizes to the ketone form thus providing the thermodynamic sink for the reaction to fall into. The imidazole ligand on the catalyst was crucial for success and may be involved in the isomerization. A very interesting example of this difficult to accomplish process.

Douglas B. Grotjahn, Casey R. Larsen, Jeffery L. Gustafson, Reji Nair, and Abhinandini Sharma: JACS 2007, DOI: 10.1021/ja073457i

Cross Coupling of Anilines

A fascinating paper appeared on the JACS ASAP site this morning from Ueno, Chatani and Kakiuchi. They used a ruthenium catalyst to carry out a cross coupling of an aryl amine with a phenyl boronate. What is remarkable is the fact that the transition metal did oxidative addition to an aryl-nitrogen bond. Success of the reaction was dependent on having a chelating carbonyl group adjacent to the amine, however, this is still the first example of oxidative addition to a hitherto unreactive C-N bond.

Satoshi Ueno, Naoto Chatani, and Fumitoshi Kakiuchi, DOI: 10.1021/ja0713431