Reaction #631994

Reaction equation

2-carbomethoxy-4,4-dimethyl-1-(2-methyl-1,3-dioxapent-1-yl)cyclohexane

vinylmagnesium bromide

vinyl bromide

HCl

→

1-(2-hydroxy-5,5-dimethyl-1-cyclohexyl)-4-penten-1-one

Yield 60.0%

Solvents

CH2Cl2 AcOEt

THF

THF

Conditions

Workup

1. 1
   TemperatureAfter 4 hours the mixture was cooled
2. 2
   ExtractionExtraction of the mixture
3. 3
   Otherwith Et2O, removal of the solvents

Procedure

A solution of 2-carbomethoxy-4,4-dimethyl-1-(2-methyl-1,3-dioxapent-1-yl)cyclohexane (5.16 g) in 10 ml of THF was added dropwise, over 15 minutes, to a solution of vinylmagnesium bromide (1.2 g) and vinyl bromide (5.35 g) in 20 ml of THF at 65° C. After 4 hours the mixture was cooled and poured into cold 20% aqueous HCl (40 ml). Extraction of the mixture with Et2O, removal of the solvents and a SiO2 chromatography (CH2Cl2/AcOEt) provide pure 1-(2-hydroxy-5,5-dimethyl-1-cyclohexyl)-4-penten-1-one (yield 60%).

Source