反应详情

温度

23 °C

A flask containing Zn(OTf)2 (Zinc triflate purchased from Fluka was found to give the best results, other vendor's proved inefficient; 557 mg, 1.50 mmol) and (−)-N-methylephedrine (275 mg, 1.50 mmol) was added toluene (1.5 mL) and Et3N (209 μL, 1.50 mmol) at 23° C. under a nitrogen atmosphere. The resulting mixture was stirred for 2 h at 23° C. before but-1-en-3-ynyl-benzene (192 μL, 1.50 mmol) was added in one portion. After stirring for 15 min at 23° C., the reaction was cooled to 0° C., then acetaldehyde (168 μL, 30.0 mmol) was added at the same temperature in one portion. The resulting mixture was warmed to 23° C. and stirred for 35 h, then quenched by the addition of saturated aqueous NH4Cl (3 mL). The mixture was poured into a separatory funnel and diluted with EtOAc (5 mL). The layers were separated and the aqueous layer was extracted with EtOAc (3×3 mL). The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. Purification of the residue via flash chromatography (0→20% EtOAc/hexanes) afforded compound 7 (106 mg, 41%, 72% ee; the ee was determined after making the acetate ester) as a pale yellow oil.

1. customto give the
2. custombest results
3. additionwas added in one portion
4. temperaturethe reaction was cooled to 0° C.
5. temperatureThe resulting mixture was warmed to 23° C.
6. stirringstirred for 35 h
7. customquenched by the addition of saturated aqueous NH4Cl (3 mL)
8. additionThe mixture was poured into a separatory funnel
9. additiondiluted with EtOAc (5 mL)
10. customThe layers were separated
11. extractionthe aqueous layer was extracted with EtOAc (3×3 mL)
12. dry with materialThe combined organic layers were dried over Na2SO4
13. filtrationfiltered
14. concentrationconcentrated in vacuo
15. customPurification of the residue via flash chromatography (0→20% EtOAc/hexanes)