Staudinger Reactions - Bioothogonal before Click Chemistry

The original bioorthogonal chemistry using azides and their reaction phosphines to form aza-ylids, which can do bioconjugation reactions and other useful transformations in organic synthesis.

The aza-ylid (aminophosphorane) generated can react directly with water in a hydrolysis reaction to give an amine product. The reduction of the azide to the amine under these conditions is mild and tolerant of many other functional groups, whereas a hydrogenation or borohydride reduction might not be. The only by-product it triphenylphosphine oxide which is inert, separable and provides a strong enthalpy driving force.

The aza-ylid can also react with carbonyl functional groups. If it reacts with a ketone or an aldehyde, you make the imine product, that can be useful in general synthesis of nitrogen containing molecules, including heterocycles.

#chemistry #organicchemistry #science