3-Methyl-2-cyclohexen-1-one → (2R,3R)-7-methyl-2,3-diphenyl-1,4-dioxaspiro[4.5]dec-6-ene

Participants

Reaction Conditions

Reaction Steps

(1R,2R)-1,2-diphenyl-1,2-ethanediol (150 g, 699 mmol) and 3-methyl-2-cyclohexen-1-one (77 g, 699 mmol) were suspended in benzene (1398 mL) and treated with PPTS (4.39 g, 17.48 mmol). The flask was fitted with a Dean-Stark trap filled with benzene and a condenser. The reaction was heated to 115° C. for 3 days, and then the reaction was cooled to ambient temperature and diluted with ether. The mixture was washed with saturated aq NaHCO3. The organic layer was dried over MgSO4, filtered and concentrated to give a red/orange liquid (214 g, 100% yield). The liquid was used without further purification.

Provenance & Evidence