Ethylene Glycol → 7,7,9,9-Tetramethyl-8-(2',4',6'-triisopropylbiphenyl-2-yl)-1,4-dioxa-8-phosphaspiro[4.5]decane

Participants

Reaction Conditions

Reaction Steps

A flask was charged with 3.75 g of 2,2,6,6-tetramethyl-1-(2′,4′,6′-triisopropylbiphenyl-2-yl)phosphinan-4-one (8.32 mmol, 1.0 equiv) and 0.16 g of p-toluenesulfonic acid monohydrate (0.84 mmol, 0.1 equiv). The atmosphere was purged with nitrogen and the flask was charged with 80 mL of nitrogen-sparged toluene. To this solution was added 4.6 mL of ethylene glycol (83 mmol, 10 equiv). The reaction flask was equipped with a Dean-Stark trap and warmed to an internal temperature of 110° C. for 2 h under nitrogen atmosphere. The distilled toluene was collected in the Dean-Stark trap. The reaction mixture was cooled to room temperature under nitrogen gas. The reaction was quenched with 1.6 mL of aqueous 10 wt % sodium carbonate solution and partitioned between 65 mL of heptane and 35 mL of water. The organic solution was washed twice with 20 mL portions of water, concentrated in vacuo with gentle heating and the residue was chased once with heptane. The concentrate was dissolved in 35 g of methanol. Seed crystals were added to induce crystallization, the solvent was removed in vacuo and 16 mL of methanol was added to the crystalline solid. The mixture was stirred overnight at room temperature and the crystalline product was isolated by filtration, washed with methanol and dried in vacuo at 50° C. to give 3.5 g of 7,7,9,9-tetramethyl-8-(2′,4′,6′-triisopropylbiphenyl-2-yl)-1,4-dioxa-8-phosphaspiro[4.5]decane (96 area % by HPLC, 82% yield).

Provenance & Evidence