Triphenylphosphine → HCID 89907088, compound

Participants

Reaction Steps

To a solution of 4-hydroxybenzophenone (2.00 g; 10.1 mmol), triphenylphosphine (4.234 g; 16.1 mmol) and (5-ethyl-2,2-dimethyl-1,3-dioxan-5-yl)methanol (2.813 g; 16.14 mmol) in anhydrous tetrahydrofuran (50 mL) at 0° C. was added diisopropyl azodicarboxylate (3.264 g; 16.14 mmol) dropwise over 10 min. The reaction mixture was stirred for 16 h at ambient temperature. TLC (eluent dichloromethane/acetone 10:1) confirmed ca 50° A) conversion. The reaction was warmed to 35-40° C. for 12 h and the conversion was monitored until ca 95° A) of 4-hydroxybenzophenone had reacted. The bright orange reaction mixture was evaporated to dryness, dissolved in dichloromethane and passed through a plug of silica. The eluent was again evaporated to dryness, redissolved in methanol (80 mL) and 1M HCl (22 mL) was added. The colourless reaction mixture was stirred for 1 h at ambient temperature, complete ketal cleavage was confirmed by TLC (eluent hexane/2-butanone 1:1). The methanol was evaporated to leave an aqueous residue. Water (150 mL) was added and the mixture was extracted with ethyl acetate (2×100 mL). The organic phase was separated, dried, evaporated and the oily crude product was purified by chromatography (eluent hexane/2-butanone 2:1→1:1). This provided the desired 2-(4-benzoylphenoxymethyl)-2-ethylpropane-1,3-diol (2.11 g; 66%) as a viscous colourless oil.

Provenance & Evidence