反应详情

To a 500 mL thee-neck round-bottomed flask equipped with argon inlet/outlet, thermometer, and magnetic stirring was added 5(S)-hydroxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylic acid methyl ester (29 g, 140 mmol) in 280 mL of toluene. The reaction was cooled in a ice-salt bath, and DPPA (36 mL, 170 mmol, Aldrich) was added (internal temp.=−4° C.). DBU (25 mL, 170 mmol, Aldrich) was added over 10 min at such a rate that the internal temp was kept below 1° C. The ice in the bath was allowed to melt, and the reaction continued for 12 h during which time the mixture stopped stirring because a precipitate had formed. Stirring was resumed, and the mixture was stirred at RT for another 11 h. The reaction contents were poured into a 2 L sep funnel, and the lower dark-brown layer was removed. Water (250 mL) was added to the remaining top layer, and the mixture was extracted with Et2O (3×250 mL). The combined organic layers were washed with 1M H3PO4, water, satd NaHCO3, and brine. The organic layer was dried over MgSO4, filtered and concentrated in vacuo. Purification by silica gel chomatography (330 g Isco Redisep® column, 1:1 hexane-CH2Cl2) of the crude material provided the title compound. MS (+ion ESI) m/z=232 (MH+).

1. customTo a 500 mL thee-neck round-bottomed flask equipped with argon inlet/outlet
2. temperatureThe reaction was cooled in a ice-salt bath
3. customwas kept below 1° C
4. stirringthe mixture stopped stirring because a precipitate
5. customhad formed
6. stirringStirring
7. stirringthe mixture was stirred at RT for another 11 h
8. customThe reaction contents
9. additionwere poured into a 2 L sep funnel
10. customthe lower dark-brown layer was removed
11. additionWater (250 mL) was added to the remaining top layer
12. extractionthe mixture was extracted with Et2O (3×250 mL)
13. washThe combined organic layers were washed with 1M H3PO4, water
14. dry with materialThe organic layer was dried over MgSO4
15. filtrationfiltered
16. concentrationconcentrated in vacuo
17. customPurification by silica gel chomatography (330 g Isco Redisep® column, 1:1 hexane-CH2Cl2) of the crude material