Iodine → 4-(3-Methylidenepentyl)oxan-4-ol

Participants

Reaction Conditions

Reaction Steps

To 8.50 g of dry magnesium shavings was added 100 ml of tetrahydrofuran and a small crystal of iodine. After 20 minutes, 0.5 ml of 1,2-dibromoethene was added using a syringe followed by the dropwise addition of 5 ml of a 70% solution of 1,1,1-tris(chloromethyl)propane in tetrahydrofuran with evolution of heat and gas. While stirring, additional 1,1,1-tris(chloromethyl)propane solution was added, to total 44.7 g at a rate to maintain reflux. The refluxing was continued for an additional 0.5 hour. Then, the reaction mixture was cooled to -62° to -43° C. and 15.0 g of 4H-pyran-4-one (Aldrich) in 20 ml of tetrahydrofuran was added dropwise. After 1 hour at -60° C., the reaction mixture was allowed to warm to -20° C. and then poured into a mixture of ice-cold diethyl ether (500 ml) and saturated ammonium chloride (350 ml). The aqueous fraction was extracted twice with 300 ml diethyl ether. The combined ether solutions were washed with saturated sodium chloride solution, dried and stripped to yield 16.52 g of the desired product as a pale yellow liquid.

Provenance & Evidence