175697-24-2Relevant academic research and scientific papers
Hydroboration Catalyzed by 1,2,4,3-Triazaphospholenes
Tien, Chieh-Hung,Adams, Matt R.,Ferguson, Michael J.,Johnson, Erin R.,Speed, Alexander W. H.
, p. 5565 - 5568 (2017)
The synthesis and study of the catalytic activity of 1,2,4,3-triazaphospholenes (TAPs) is reported. TAPs represent a more modular scaffold than previously reported diazaphospholenes. TAP halides were shown to catalyze the 1,2 hydroboration of 19 imines, and three α,β unsaturated aldehydes with pinacolborane, including examples that did not undergo hydroboration by previously reported diazaphospholene systems. DFT calculations support a mechanism where a triazaphospholene cation interacts with the substrate, a mechanism distinct from diazaphospholene catalyzed hydroborations.
Asymmetric Imine Hydroboration Catalyzed by Chiral Diazaphospholenes
Adams, Matt R.,Tien, Chieh-Hung,McDonald, Robert,Speed, Alexander W. H.
supporting information, p. 16660 - 16663 (2017/12/13)
The first use of diazaphospholenes as chiral catalysts has been demonstrated with enantioselective imine hydroboration. A chiral diazaphospholene prepared in a simple three-step synthesis from commercial materials has been shown to achieve the highest enantioselectivity for the hydroboration of alkyl imines with pinacolborane reported to date. Enantiomer ratios of up to 88:12 were obtained with low (2 mol %) catalyst loadings. Twenty examples of asymmetric reduction employing this main-group catalysis protocol, including the synthesis of the pharmaceuticals ent-rasagiline and fendiline, are shown.
Application of tris(trimethylsilyl) phosphite as a convenient phosphorus nucleophile in the direct synthesis of tetrasubstituted α-aminophosphonic acids from ketimines
Boduszek, Bogdan,Olszewski, Tomasz K.
, p. 173 - 179 (2017/03/06)
The condensation of tris(trimethylsilyl) phosphite with various ketimines leads directly to tetrasubstituted a-aminophosphonic acids. The presented reaction proceeds readily at room temperature and provides labile silylated esters of tetrasubstituted a-aminophosphonic acids, as non-isolable reaction intermediates. Subsequent methanolysis of the latter provides the desired á-aminophosphonic acids bearing an fully substituted á-carbon in good overall yields as crystalline non-hygroscopic solids after simple recrystallization from a methanol-acetone mixture.nordstom.
