Safe and Selective Nitro Group Reductions Catalyzed by Sustainable and Recyclable Fe/ppm Pd Nanoparticles in Water at Room Temperature

Abstract

As a result of a unique synergy between ligand‐free Fe/ppm Pd nanoparticles and PEG‐containing designer surfactants, a facile and selective reduction of nitro‐containing aromatics and heteroaromatics can be effected in water at room temperature in the presence of NaBH4. This new nanotechnology involves low catalyst loadings, is highly chemoselective, and tolerates a wide variety of functional groups. The process, which includes recycling of the entire aqueous medium, offers a general, environmentally responsible, and notably safe approach to highly valued reductions of nitro‐containing compounds.

Evolution of Solvents in Organic Chemistry

“…Our recent results have also demonstrated the practicality of Fe/ppm Pd nanoparticles (NPs) as a catalyst for selective reductions of nitro groups in the presence of a variety of other functionality. , Here, too, the same high efficiency was observed (conversion of 2 to 3 , Scheme ). This process is all the more remarkable as it takes place without requiring a high pressure vessel, after careful design of the process and using KBH 4 (rather than NaBH 4 in this case) as the optimum hydride source .…”

“…However, by simply leaving the ligand out of this recipe, the resulting NPs, while unsuitable for SM couplings, have been found to reduce functionalized aromatic and heteroaromatic nitro-containing compounds in water at room temperature in high yields (Scheme ). , Even less palladium is required in these reductions, with amounts on the order of 80–100 ppm or so found to be sufficient. NaBH 4 was identified as the best choice as the source of hydride.…”

Cascade Processes with Micellar Reaction Media: Recent Advances and Future Directions

“…The desired diyne product was achieved with an 80% isolated yield [ 119 ]. Selective nitro-group reductions could have also been performed using iron particles with ppm levels of palladium [ 120 , 121 ] in TPGS-750-M. Such capabilities have been used as the foundation of multistep, one-pot reactions [ 122 ].…”

Aminations of Aryl Halides Using Nitroaromatics as Coupling Partners: Overcoming the Hydrodehalogenation Pathway under a Hydrogen Atmosphere in Water

“…44 Similar selectivity was observed with the 1,4-reductions of chalcones and nitroarenes. 45,46 ■ RESULTS AND DISCUSSION A proline-derived amphiphile PS-750-M 47−51 possesses structural features that could assist in stabilizing nanoparticles in water for chemocatalysis. 42,44,52,53 Thus, having a bimetallic nanoparticle catalyst composed of ligated Pd and another hydride-forming metal proximal to the Pd could perform selective catalysis, avoiding hydrodehalogenation.…”