Diisopropylamine → HCID 58460172, compound

Participants

Reaction Conditions

Reaction Steps

A 1.6M solution of n-butyl lithium (81 mL, 130 mmol) was added to a stirred solution of diisopropylamine (18.26 mL) in methyl-THF (150 mL) at −10° C. The resulting solution was stirred at −10° C. for 15 mins. 1,2-cyclohexanedione (6.84 g) was added to the reaction mixture as a solution in methyl-THF (30 mL). During the addition the internal temperature of the reaction was maintained between −15° C. and −5° C. by modulation of delivery rate. The resulting dark orange/brown solution was stirred at −10 to −20° C. for a further 15 mins. The reaction mixture was then cooled to −50° C. and benzyl bromoacetate (12.62 mL, 79 mmol) was added dropwise via syringe. The mixture was stirred at this temperature for 10 minutes then aged at −78° C. for 1½ hours. The reaction mixture was quenched at −78° C. by dropwise addition of 1M HCl (300 ml). Ethyl acetate (200 mL) was added and the mixture allowed to warm to room temperature. The layers were separated and the organic phase washed with saturated brine (150 mL) and dried over sodium sulfate then reduced in vacuo. The resulting solid was purified by column chromatography, eluting with 0-25% ethyl acetate in cyclohexane. The appropriate fractions were reduced in vacuo to provide the product as a 1:1 mixture of thermodynamic enol:kinetic enol (registered as thermodynamic enol)

Provenance & Evidence