1,2-Dibromoethane → 1H-Indene, 3,3'-(1,2-ethanediyl)bis[4,7-dimethyl-

HRID 865317Notes

Reaction equation

[CH3:1][C:2]1[CH:10]=[CH:9][C:8]([CH3:11])=[C:7]2[C:3]=1[CH:4]=[CH:5][CH2:6]2.[CH2:12]([Li])[CH2:13][CH2:14][CH3:15].C[C:18]1[CH:26]=[CH:25][C:24](C)=[C:23]2[C:19]=1[CH:20]=[CH:21][CH:22]2[Li].BrCCBr>O1CCCC1.O>[CH3:1][C:2]1[CH:10]=[CH:9][C:8]([CH3:11])=[C:7]2[C:3]=1[C:4]([CH2:15][CH2:14][C:13]1[C:12]3[C:20](=[C:19]([CH3:23])[CH:18]=[CH:26][C:25]=3[CH3:24])[CH2:21][CH:22]=1)=[CH:5][CH2:6]2

Participants

Conditions

Temperature: 0 °C

Procedure

38.2 g (265 mmol) of 4,7-dimethylindene was dissolved in 350 ml of tetrahydrofuran and the solution was cooled to 0° C. Then 165 ml of n-butyllithium (1,6M in hexane, 264 mmol) was added dropwise over 2.5 hours. After warming to room temperature and stirring for 4 hours a purple solution of 4,7-dimethylindenyl-lithium was obtained. This solution was cooled to -70° C. and treated dropwise with 25,3 g of 1,2-dibromoethane (135 mmol) in 15 ml of tetrahydrofuran over 35 min. After warming to room temperature, a pale yellow solution was obtained, and then water was added. The organic phase was collected and dried over Na2SO4. The solvent was removed by vacuum evaporation to provide 20 g of crude product (48% yield).

Workup

temperatureAfter warming to room temperature
customwas obtained
temperatureThis solution was cooled to -70° C.
temperatureAfter warming to room temperature
customa pale yellow solution was obtained
customThe organic phase was collected
dry with materialdried over Na2SO4
customThe solvent was removed by vacuum evaporation

Sources & evidence

ORD record: ord-d661a9859bd947ce97004226853d618c
Source dataset: uspto-grants-1996_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05565533

Reaction notes

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