Allyl bromide → 2-Allyl-6-methoxy-tetralin-1-one

HRID 2207158Notes

Reaction equation

[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[CH3:11][O:12][C:13]1[CH:14]=[C:15]2[C:20](=[CH:21][CH:22]=1)[C:19](=[O:23])[CH2:18][CH2:17][CH2:16]2.CN(P(N(C)C)(N(C)C)=O)C.[CH2:35](Br)[CH:36]=[CH2:37]>C1COCC1>[CH2:37]([CH:18]1[CH2:17][CH2:16][C:15]2[C:20](=[CH:21][CH:22]=[C:13]([O:12][CH3:11])[CH:14]=2)[C:19]1=[O:23])[CH:36]=[CH2:35]

Participants

Conditions

Temperature: -78 °C

Procedure

To a solution of LiHMDS (1.04 g, 6.24 mmol), in THF (40 mL) cooled at −78° C. is added slowly a solution of 6-methoxy-1-tetralone (1.0 g, 5.67 mmol) in anhydrous THF (40 mL). After the addition is complete, the solution is stirred at −78° C. for 30 minutes, then HMPA (1.97 mL, 11.3 mmol) is slowly added and the mixture is stirred for other 5 minutes followed by the addition of a solution of allyl bromide (0.74 mL, 8.5 mmol) in anhydrous THF (5 mL). The mixture is left to warm slowly to room temperature (2-3 h) and quenched at 0° C. with aqueous 1N HCl (20 mL), then extracted with diethylether. The organic phase is dried over MgSO4 and concentrated to dryness. The residue is purified by column chromatography on SiO2 (Petroleum Ether/EtOAc=95:5) to afford the title compound 53 as a colorless oil (Yield 0.56 g, 45%).

Workup

additionAfter the addition
stirringthe mixture is stirred for other 5 minutes
waitThe mixture is left
temperatureto warm slowly to room temperature (2-3 h)
customquenched at 0° C. with aqueous 1N HCl (20 mL)
extractionextracted with diethylether
dry with materialThe organic phase is dried over MgSO4
concentrationconcentrated to dryness
customThe residue is purified by column chromatography on SiO2 (Petroleum Ether/EtOAc=95:5)

Sources & evidence

ORD record: ord-bbf2457e46954ad488d68a086578249b
Source dataset: uspto-grants-2016_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09376387B2

Reaction notes

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