反応 #1552100

反応方程式

methylmagnesium iodide

2,6-dibromo-9H-xanthen-9-one

AcOH

→

2,6-dibromo-9-methylene-9H-xanthene

収率 64.7%

溶媒

EtOAc

THF

反応条件

後処理

1. 1
   温度The reaction mixture was cooled to 0° C.
2. 2
   その他quenched with saturated NH4Cl solution (250 mL)
3. 3
   workup.STIRRINGstirred for 30 min
4. 4
   その他The volatiles were removed in vacuo
5. 5
   その他the organic layer was separated
6. 6
   抽出the aqueous phase was extracted with CHCl3 (2×200 mL)
7. 7
   乾燥combined organics was dried over MgSO4
8. 8
   ろ過filtered
9. 9
   その他solvents removed in vacuo to crude product (9.46 g)
10. 10
    その他The crude reaction
11. 11
    workup.STIRRINGthe reaction mixture was stirred at room temperature for 3 hrs
12. 12
    その他the volatiles removed in vacuo
13. 13
    その他the residue was precipitated from isohexanes

実験手順

Referring to Scheme 10, methylmagnesium iodide (14.12 mL, 3 M in Et2O, 42.4 mmol) was added to a stirred solution of 2,6-dibromo-9H-xanthen-9-one (7-2) (10 g, 28.2 mmol) in THF (30 mL) at 0° C. The reaction mixture was allowed to warm up to rt and stirred for 2 h. The reaction mixture was cooled to 0° C. and quenched with saturated NH4Cl solution (250 mL) and stirred for 30 min. The volatiles were removed in vacuo. The residue was taken up in CHCl3 (200 mL), and the organic layer was separated and the aqueous phase was extracted with CHCl3 (2×200 mL) and combined organics was dried over MgSO4, filtered and solvents removed in vacuo to crude product (9.46 g). The crude reaction was taken up in EtOAc (200 mL) and AcOH was added (20 mL) and the reaction mixture was stirred at room temperature for 3 hrs, the volatiles removed in vacuo and the residue was precipitated from isohexanes to give 2,6-dibromo-9-methylene-9H-xanthene (9-1) (6.43 g, 64.7% yield).

出典