Iodine → [2-(1,3-Dioxolan-2-yl)phenyl]diphenylphosphine oxide

Participants

Reaction Conditions

Reaction Steps

A solution of 45.8 g of the preceding compound in 125 ml of ether was added dropwise to 5.5 g of magnesium in 150 ml of ether. The mixture was stirred and heated under argon with a few iodine crystals then agitated by sonication for 18 hours. The ether was boiled off and replaced with 150 ml of tetrahydrofuran. The mixture was heated to 50° C. and remained exothermic to completion. After 3 hours the mixture was cooled in an ice bath and 36 ml of diphenylphosphine chloride diluted with 12 ml of dry tetrahydrofuran was added over a 30 minute period. The mixture was heated at 40° C. for 2 hours then cooled in an ice/salt bath. Then 250 ml of a concentrated solution of ammonium chloride was added portionwise over a 30 minute period. The layers were separated and the aqueous layer was extracted twice with 250 ml portions dichloromethane. The dichloromethane extracts and the above tetrahydrofuran layer were combined and dried over magnesium sulfate. The mixture was filtered and the filtrate was evaporated to give a yellow cloudy syrup. The syrup was extracted with 500 ml of boiling ether. The extract was cooled to give pale yellow crystals. The crystals were collected and recrystallized from acetone to give 11.3 g of [2-(1,3-dioxolan-2-yl)phenyl]diphenylphosphine oxide, mp 161°-162° C.

Provenance & Evidence