Phenyl-2,2-Dimethyl-l,3-Propanediol

A mixture of benzaldehyde (0.1 mol) and isobutyraldehyde (0.2 mol) was added into a three-necked round-bottomed flask fitted with a condenser. An exothermic reaction started when a solution of KOH (0.1 mol) in absolute ethanol (90 mL) was added dropwise. When the temperature of the mixture had reached 50 °C, the flask was cooled by a water bath. The reaction mixture was heated at 50-60 °C for 5 h and then evaporated at aspirator vacuum. Water (100 mL) was added to the remaining residue and this mixture was filtered after it was put for 12 h. The crude product was obtained, which can be purified by crystallization from toluene. The purified product was white solid with 85 % yield, m.p. 80.2-81.0 °C. 

Phosphorus trichloride (0.11 mol) was added slowly to a solution of 1-phenyl- 

2- dichloroethane (40 mL) and cooled by an ice-water bath. After stirring at 5-10 °C for 2 h, a solution of absolute ethanol in 1,2-dichloroethane (30 mL) was added dropwise and the reaction solution was heated under reflux for 1.5 h then evaporated. The residue was purified by crystallization from toluene to give 5,5-dimethyl-4-phenyl-l,3,2-dioxaphosphorinan-2-one M18-1 or 5,5-dimethyl-l,3,2-dioxaphosphorinan-2-one M18-2 with 90 % yield, as a white solid, m.p. M18-1 170-172 °C, M18-2 56-58 °C. 

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