Recent advances in metal-mediated nitrogen oxyanion reduction using reductively borylated and silylated N-heterocycles

Abstract

Silylated and borylated N-heterocycles exhibit efficacy for the reduction of nitrogen oxyanions coordinated to first row transition metals.

Facile Deoxygenative Reduction of a Bridging Carbonato Ligand with Silyl and Boryl 4,4’-Bipyridinylidene Reagents

“…Co 0 CO therefore explored the reaction of 2 with the reducing agents N,Nʹ-bis(trimethylsilyl)- [6] and N,Nʹ-bis(pinacolatoboryl)-4,4ʹ-bipyridinylidene [13] that have been successfully applied in reductive deoxygenation reactions of coordinated nitrogen oxides. [9] Starting with the silyl substituted reagent, addition of 1.5 equivalents of N,Nʹ-bis(trimethylsilyl)-4,4ʹ-bipyridinylidene (Me3Si-bipy) to 2 in toluene and heating to 80 °C over 18h (Scheme 3) resulted in the formation of a new diamagnetic Co(I) species noted by the appearance of a new resonance at 44.2 ppm in the 31 P{ 1 H} NMR spectrum. Analysis of the 1 H NMR spectrum of the reaction mixture displayed a peak at 0.09 ppm corresponding to the silyl methyl protons in the product, suggesting the formation of a Co(I) siloxide species, 3.…”

“…extensively in the context of reduction and deoxygenation of a nitrogen oxides in a variety of systems. [9] To our knowledge, the use of these reagents for the deoxygenation of coordinated carbonates has been less explored.…”

Facile Deoxygenative Reduction of a Bridging Carbonato Ligand with Silyl and Boryl 4,4’‐Bipyridinylidene Reagents

“…We therefore explored the reaction of 2 with the reducing agents N,N'-bis(trimethylsilyl)- [6] and N,N'-bis(pinacolatoboryl)-4,4'bipyridinylidene [13] that have been successfully applied in reductive deoxygenation reactions of coordinated nitrogen oxides. [9] Starting with the silyl substituted reagent, addition of 1.5 equivalents of N,N'-bis(trimethylsilyl)-4,4'-bipyridinylidene (Me 3 Si-bipy) to 2 in toluene and heating to 80 °C over 18 h (Scheme 3) resulted in the formation of a new diamagnetic Co(I) species noted by the appearance of a new resonance at 44.2 ppm in the 31 P{ 1 H} NMR spectrum. Analysis of the 1 H NMR spectrum of the reaction mixture displayed a peak at 0.09 ppm corresponding to the silyl methyl protons in the product, suggesting the formation of a Co(I) siloxide species, 3.…”

“…For example, Caulton and co-workers have explored these reductants extensively in the context of reduction and deoxygenation of a nitrogen oxides in a variety of systems. [9] To our knowledge, the use of these reagents for the deoxygenation of coordinated carbonates has been less explored.…”

“…Furthermore, these reagents incorporate silicon and boron electrophiles that drive reactions through the formation of thermodynamically favorable silicon/boron halogen or oxygen bonds. For example, Caulton and co‐workers have explored these reductants extensively in the context of reduction and deoxygenation of a nitrogen oxides in a variety of systems [9] . To our knowledge, the use of these reagents for the deoxygenation of coordinated carbonates has been less explored.…”