Dimethylformamide → (1S)-1-(2-{[tert-Butyl(diphenyl)silyl]oxy}ethyl)-3,4-dihydro-1H-2-benzopyran-6-carbaldehyde

HRID 2056758Notes

Reaction equation

[Si:1]([O:18][CH2:19][CH2:20][C@H:21]1[C:26]2[CH:27]=[CH:28][C:29](Br)=[CH:30][C:25]=2[CH2:24][CH2:23][O:22]1)([C:14]([CH3:17])([CH3:16])[CH3:15])([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C([Li])CCC.CN(C)[CH:39]=[O:40]>C1COCC1>[Si:1]([O:18][CH2:19][CH2:20][C@H:21]1[C:26]2[CH:27]=[CH:28][C:29]([CH:39]=[O:40])=[CH:30][C:25]=2[CH2:24][CH2:23][O:22]1)([C:14]([CH3:17])([CH3:16])[CH3:15])([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

Conditions

Temperature: -78 °C

Procedure

To a stirred solution of 2-((1S)-6-bromo-3,4-dihydro-1H-2-benzopyran-1-yl)ethyl tert-butyl(diphenyl)silyl ether (2.5 g, 5.05 mmol) in dry THF (60 mL), cooled to −78° C. under nitrogen, was slowly added n-butyllithium (2.5M in THF) (5.4 mL, 13.5 mmol). After 30 min stirring at −78° C., dry dimethylformamide (3.5 mL, 45 mmol) was added and the reaction allowed to warm to room temperature overnight. The reaction was quenched by addition of water and extracted into ethyl acetate. The combined organic extracts were washed with brine, dried (MgSO4), filtered and evaporated in vacuo. The resultant yellow oil was purified by flash chromatography on silica, eluting with ethyl acetate/hexane (0:4 to 1:3), to yield the title compound as a colourless oil.

Workup

temperatureto warm to room temperature overnight
customThe reaction was quenched by addition of water
extractionextracted into ethyl acetate
washThe combined organic extracts were washed with brine
dry with materialdried (MgSO4)
filtrationfiltered
customevaporated in vacuo
customThe resultant yellow oil was purified by flash chromatography on silica
washeluting with ethyl acetate/hexane (0:4 to 1:3)

Sources & evidence

ORD record: ord-dee50f8e298343cb8e5f5d6f87e2daca
Source dataset: uspto-grants-2008_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07335660B2

Reaction notes

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