A new trick for an old dog

I am writing this from Shanghai, China, where I am attending the 6^th International Forum on Homogeneous Catalysis, organized by Professors Shengming Ma and Yong Tang. Tonight I want to talk about a really neat process developed in Professor Daniel Seidel’s lab at Rudgers University. His team has come up with some interesting and surprising reactions that raise eyebrows as they push the envelope in organic reactivity and show how one can extract new possibilities out of some well-established reactions. Below you see what is to be reasonably expected of an amine, an aldehyde, and an enolizable ketone. Of course, this corresponds to the good old Mannich reaction, which is a trusted friend of many organic chemists. Daniel has put a new twist on this process and developed conditions that lead to a regiochemically different outcome. His Org. Lett. paper describes this advance and traces the origins of the observed selectivity to the formation of an azomethide ylide intermediate. This departure is responsible for the product formation (the initially formed ylide undergoes isomerization). This is not the first process in which the Seidel lab was able to re-route iminium reactivity to an alternate pathway. The toolbox they have developed is some very clever stuff.