Silanes as Reagents for the Deoxygenation of Tertiary Phosphine Oxides – A Case Study for the Deoxygenation of 5-Membered Cyclic Phosphine Oxides
The possibilities for the deoxygenation of 3-methyl-1-phenyl-3-phospholene 1-oxide were investigated using
different silanes. Cl3SiH and PhSiH3 were efficient, but they have disadvantages regarding user-friendliness and price,
respectively. Tetramethyldisiloxane and polymethylhydrosiloxane that are cheap and user-friendly, but are of lower
reactivity could be applied at 110 °C in toluene solution, without the use of any catalyst successfully. Then, the
deoxygenation was extended to other 1-phenylphospholene oxides and phospholane oxides. The cyclic phosphines useful
as ligands in transition metal complexes were identified as their sulfides and boranes. The catalyst-free method elaborated
seems to be of more general value.
Keywords: Cyclic phosphine/phosphane oxides, phospholene oxides, deoxygenation, silanes, phosphines/phosphanes,
phosphine/phosphane sulfides, phosphine boranes, user friendly reagents.
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