Mechanochemical Phosphorylation of Acetylides Using Condensed Phosphates: A Sustainable Route to Alkynyl Phosphonates

Solvent-free mechanochemical phosphorylationof acetylidesusing condensed phosphates, a more sustainable route to alkynyl phosphonatesand organophosphorus chemicals. In pursuit of a more sustainable route to phosphorus-carbon(P-C) bond-containing chemicals, we herein report that phosphonatescan be prepared by mechanochemical phosphorylation of acetylides usingpolyphosphates in a single step, redox-neutral process, bypassingwhite phosphorus (P-4) and other high-energy, environmentallyhazardous intermediates. Using sodium triphosphate (Na5P3O10) and acetylides, alkynyl phosphonates 1 can be isolated in yields of up to 32%, while reaction ofsodium pyrophosphate (Na4P2O7) andsodium carbide (Na2C2) engendered, in an optimizedyield of 63%, ethynyl phosphonate 2, an easily isolablecompound that can be readily converted to useful organophosphoruschemicals. Highly condensed phosphates like Graham's salt andbioproduced polyphosphate were also found to be compatible after reducingthe chain length by grinding with orthophosphate. These results demonstratethe possibility of accessing organophosphorus chemicals directly fromcondensed phosphates and may offer an opportunity to move toward agreener phosphorus industry.

Automated summary

Solvent-free mechanochemical phosphorylation of acetylides using condensed phosphates provides a more sustainable method for synthesizing alkynyl phosphonates and organophosphorus chemicals.