反应详情

A solution of 11.1 g. of 2-bromobenzhydryl methyl ether in 23 ml. of tetrahydrofuran and 7 ml. of hexane is cooled to -50°C. and 22 ml. of butyllithium is introduced while maintaining the temperature below -50°C. The solution is stirred for 2 hours at -60° to -70°C. To the suspension is then added a solution of 5 g. of 4-oxo-tetrahydropyran in 5 ml. of tetrahydrofuran over a span of a few minutes. The mixture is stirred at -60°C. for 3 hours and at ambient temperature overnight. Ice-water is added, the organic layer is separated, the aqueous layer is extracted with methylene chloride and the combined organic solutions are dried over sodium sulfate. The solvent is removed under reduced pressure and subjected to column chromatography over alumina. Elution with benzene removes benzhydryl methyl ether, and the column is then eluted with diethyl ether. The solid obtained is heated at reflux in 60 ml. of glacial acetic acid, and then the solvent is removed under reduced pressure to leave a crystalline solid. This solid is recrystallized from hexane to give 1,2',3,3',5',6'-hexahydro-3-phenylspiro[isobenzofuran-1,4'-pyran] as colorless crystals, m.p. 132° - 134°C.

1. temperaturewhile maintaining the temperature below -50°C
2. additionTo the suspension is then added a solution of 5 g
3. customover a span of a few minutes
4. stirringThe mixture is stirred at -60°C. for 3 hours and at ambient temperature overnight
5. customthe organic layer is separated
6. extractionthe aqueous layer is extracted with methylene chloride
7. dry with materialthe combined organic solutions are dried over sodium sulfate
8. customThe solvent is removed under reduced pressure
9. washElution with benzene
10. customremoves benzhydryl methyl ether
11. washthe column is then eluted with diethyl ether
12. customThe solid obtained
13. temperatureis heated
14. temperatureat reflux in 60 ml
15. customof glacial acetic acid, and then the solvent is removed under reduced pressure
16. customto leave a crystalline solid
17. customThis solid is recrystallized from hexane