Arsenic Catalysis: Hydroboration of Aldehydes Using a Benzo‐Fused Diaza‐benzyloxy‐arsole

Abstract

The first example of a homogenous As catalyst for hydroboration has been established. The reaction of N,N'-diisopropylbenzene diamine or toluene-3,4-dithiol with AsCl yielded the chloroarsoles (1 and 2), which upon reaction with benzyl alcohol yielded the benzyloxy benzo-1,3,2-diazaarsole (3) and benzo-1,3,2-dithiaarsole (4), respectively. Compound 3 was found to be an excellent catalyst for the hydroboration of aldehyde substrates.

Nitrenium Salts in Lewis Acid Catalysis

“…It was found that bis(amino) ligands were necessary to isolate stable crystalline ions, as previously observed by Arduengo with imidazol‐2‐ylidenes . Related silyene, germylene, phosphenium and arsenium ions have also been reported . In 2011, Gandelman demonstrated that nitrenium cations can serve as ambiphilic ligands on rhodium and that they behave as weak σ‐donors but considerable π‐acceptors .…”

“…Over the last decade there has been increasing interest in studying pnictogens, often considered Lewis basic given the availability of an energetically accessible lone pair, in this unconventional role. This work has been expanded to include compounds of phosphorus, arsenic, antimony, and bismuth . By contrast, the reactivity of nitrogen‐containing compounds as Lewis acids has been investigated to a much lesser extent, largely due to the dearth of such species.…”

Nitrenium Salts in Lewis Acid Catalysis

“…Traditional examples of main-group Lewis acid catalysts involve group 13 and 14 elements as the central locus of reactivity,a stheyf eature al ow-lying orbital for substrate activation. [1] Over the last decade there has been increasing interest in studying pnictogens,o ften considered Lewis basic given the availability of an energetically accessible lone pair, in this unconventional role.T his work has been expanded to include compounds of phosphorus, [2][3][4][5][6][7][8][9][10][11] arsenic, [12] antimony, [13][14][15][16][17][18][19][20] and bismuth. [21][22][23] By contrast, the reactivity of nitrogen-containing compounds as Lewis acids has been investigated to am uch lesser extent, largely due to the dearth of such species.C hloramines,n itrenes,d iazocarboxylates,azides,and diazonium salts have been shown to possess N-centered electrophilic behavior.…”

“…[30] Related silyene,germylene,phosphenium and arsenium ions have also been reported. [12,[31][32][33][34] In 2011, Gandelman demonstrated that nitrenium cations can serve as ambiphilic ligands on rhodium and that they behave as weak s-donors but considerable pacceptors. [35] Stoichiometric investigations of these ions with Lewis bases were also undertaken by Gandelman, demonstrating that the Lewis acidic centre is primarily located on the internal nitrogen ( Figure 1).…”

Cadmium(II)‐Loaded Fe3O4@MPTS Nanoparticles: Preparation and Application as Catalyst for C‐N Coupling Reactions

“…However, toxic metal salts involving As, Pb, Hg, Cd, etc. still being used as the homogeneous catalysts for the specific organic transformations . Only a few reports are available for the use of these sorbents in achieving the dual objective of remediation and catalysis applications …”