反应详情

2.2 g (8.92 mmol) of 3-chloro-4,4-dimethoxy-1,5-dimethyl-8-oxa-bicyclo[3.2.1]oct-6-en-2-one in 240 ml of toluene are degassed, with heating at reflux temperature, and a catalytic amount of 66 mg of azaisobutyronitrile (AIBN) and a solution of 5.9 ml (22.3 mmol) of tributyltin hydride are added in succession. The reaction mixture is maintained at reflux temperature for a further 20 minutes to complete the reaction (TLC monitoring: hexane/ethyl acetate 4:1). The reaction mixture is then concentrated by evaporation under reduced pressure. The residue is then taken up in acetonitrile and the tin-containing residues are extracted by means of hexane. The acetonitrile phase is concentrated by evaporation in vacuo, 1.56 g (82.4% of theory) of 4,4-dimethoxy-1,5-dimethyl-8-oxa-bicyclo[3.2.1]oct-6-en-2-one remaining behind in the form of a yellow oil, which can be used for the next reaction step without further purification.

1. temperaturewith heating
2. temperatureat reflux temperature
3. temperatureThe reaction mixture is maintained
4. temperatureat reflux temperature for a further 20 minutes
5. concentrationThe reaction mixture is then concentrated by evaporation under reduced pressure
6. additionthe tin-containing residues
7. extractionare extracted by means of hexane
8. concentrationThe acetonitrile phase is concentrated by evaporation in vacuo, 1.56 g (82.4% of theory) of 4,4-dimethoxy-1,5-dimethyl-8-oxa-bicyclo[3.2.1]oct-6-en-2-one remaining behind in the form of a yellow oil, which
9. customcan be used for the next reaction step without further purification