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

Abstract

In pursuit of a more sustainable route to phosphorus−carbon (P−C) bond-containing chemicals, we herein report that phosphonates can be prepared by mechanochemical phosphorylation of acetylides using polyphosphates in a single step, redoxneutral process, bypassing white phosphorus (P 4 ) and other high-energy, environmentally hazardous intermediates. Using sodium triphosphate (Na 5 P 3 O 10 ) and acetylides, alkynyl phosphonates 1 can be isolated in yields of up to 32%, while reaction of sodium pyrophosphate (Na 4 P 2 O 7 ) and sodium carbide (Na 2 C 2 ) engendered, in an optimized yield of 63%, ethynyl phosphonate 2, an easily isolable compound that can be readily converted to useful organophosphorus chemicals. Highly condensed phosphates like Graham's salt and bioproduced polyphosphate were also found to be compatible after reducing the chain length by grinding with orthophosphate. These results demonstrate the possibility of accessing organophosphorus chemicals directly from condensed phosphates and may offer an opportunity to move toward a "greener" phosphorus industry.

Cost-effective phosphates redox-neutral transformation to bench-stable phosphorylation precursor

“…The hydride phosphorylation using condensed phosphates was also used to produce alkynyl phosphonates (Fig. 1d) 44 . Cummins further investigated the reaction of P2O5 with specific N-donor bases to form adducts like P2O5L2 and P4O10L3 (where L represents N-donor bases) 17,45 , which were effective in phosphorylation reactions (Fig.…”

Mechanocatalytic Synthesis of Ammonia by Titanium Dioxide with Bridge‐Oxygen Vacancies: Investigating Mechanism from the Experimental and First‐Principle Approach

“…Mechanochemistry, typically realized through ball milling, is an emerging method of initiating or accelerating chemical reactions by mechanical energy obtained by shearing, grinding, stretching, cavitation, and high pressure. [26][27][28][29] By creating fresh-reactive surfaces, highly active vacancies, or transient hot spots from the collisions with milling media and catalysts, new reaction routes or unexpected products (e.g., inorganic synthesis, [30][31][32][33] organic synthesis, [34][35][36][37] gas synthesis, [38,39] and others [40] ) can be achieved even under mild conditions. [25] The concept of mechanochemical N 2 fixation to directly synthesize NH 3 was initially raised in 1961.…”

A Greener Vision for P–C Bond Formation

“…In this issue of ACS Central Science , Cummins and co-workers report the mechanochemical phosphorylation of acetylides, enabling a “greener” phosphorus industry and suggesting new disconnections in organophosphorus synthesis. 1 Organophosphonate compounds are not only widely used as pharmaceuticals, flame retardants, and more but also play a prominent role as reagents in chemical synthesis (e.g., the Horner–Wadsworth–Emmons reaction). 2 …”

“… Comparison of P–C bond formation strategies via the current P 4 paradigm and the mechanochemical strategy reported by Cummins et al. 1 …”