Phosphorus fluoride exchange: Multidimensional catalytic click chemistry from phosphorus connective hubs

Summary

Phosphorus fluoride exchange (PFEx) represents a cutting-edge advancement in catalytic click-reaction technology. Drawing inspiration from nature's phosphate connectors, PFEx facilitates the reliable coupling of P(V)–F loaded hubs with aryl alcohols, alkyl alcohols, and amines to produce stable, multidimensional P(V)–O and P(V)–N linked products. The rate of P–F exchange is significantly enhanced by Lewis amine base catalysis, such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). PFEx substrates containing multiple P–F bonds are capable of selective, serial exchange reactions via judicious catalyst selection. In fewer than four synthetic steps, controlled projections can be deliberately incorporated along three of the four tetrahedral axes departing from the P(V) central hub, thus taking full advantage of the potential for generating three-dimensional diversity. Furthermore, late-stage functionalization of drugs and drug fragments can be achieved with the polyvalent PFEx hub, hexafluorocyclotriphosphazene (HFP), as has been demonstrated in prior research.