Oxidation of 3-Phenyl-1-Propanol using a Catalytic Oxoammonium SaltOxidation of 3-Phenyl-1-Propanol using a Catalytic Oxoammonium Salt
SyntheticPage 706
Published Nov 30, 2013
To a 250 mL round bottom flask equipped with a stir bar, was added 3-phenylpropan-1-ol (4.09 g, 30 mmol, 1 equiv) and DCM (75 mL, 0.4 M solution of alcohol). The oxoammonium salt (1.08 g, 6 mmol, 0.2 equiv2) was added to the solution. While stirring, commercial bleach (37.5 mL, 30 mmol, 1.0 equiv3) was added all at once where the solution turned from yellow to bright red color. The solution was allowed to stir vigorously at room temperature for 60 min and monitor by GC-MS to assure reaction completion. Once the reaction is complete, the solution was transferred to a separatory funnel and diluted with 50 mL of deionized water and extract with DCM (3 X 50 mL). The combined organic layers were washed with 100 mL of brine and dried over sodium sulfate. The solvent was removed in vacuo by rotary evaporation, affording the crude aldehyde.
The crude alcohol was then adhered to silica gel by mixing it with 1.5 weight equivalents silica gel (relative to the theoretical yield, in this case ≈ 6 g), dissolving it in CH2Cl2 (50 mL) and removing the solvent in vacuo by rotary evaporation. A plug of silica was then assembled. This was done by adding 3-4 weight equivalents of silica (again relative to the theoretical yield) to a 150 mL coarse-porosity fritted glass funnel. An appropriately sized piece of filter paper relative to the size of the funnel was used to the top of the dry silica gel layer and this layer was pre-wet with hexanes. The dry packed material was gentle added evenly atop the filter paper. Another piece of appropriately sized filter paper was added atop this layer. The desired alcohol was eluted off the plug via a 95:5 by volume mixture of Hex:EtOAc (3 column volumes). The solvent was removed in vacuo by rotary evaporation to afford the pure aldehyde (2.21 g, 55%)4 as a clear, colorless oil.