Diisopropylamine → 1,1,4,4,7-Pentamethyl-6-ethynyl-1,2,3,4-tetrahydronaphthalene

HRID 2259994Notes

Reaction equation

C([Li])CCC.C(NC(C)C)(C)C.[CH3:13][C:14]1[C:15]([C:28]([CH3:30])=O)=[CH:16][C:17]2[C:18]([CH3:27])([CH3:26])[CH2:19][CH2:20][C:21]([CH3:25])([CH3:24])[C:22]=2[CH:23]=1.P(Cl)(OCC)(OCC)=O.C([N-]C(C)C)(C)C.[Li+]>C1COCC1>[CH3:13][C:14]1[C:15]([C:28]#[CH:30])=[CH:16][C:17]2[C:18]([CH3:27])([CH3:26])[CH2:19][CH2:20][C:21]([CH3:24])([CH3:25])[C:22]=2[CH:23]=1

Participants

Conditions

Temperature: -78 °C

Procedure

n-Butyllithium was added to a solution of freshly distilled diisopropylamine (3.01 mL, 21.5 mmol) and THF (41 mL) at 0° C. under argon. After 10 min, the solution was cooled to -78° C. and a solution of methyl (5,6,7,8-tetrahydro-3,5,5,8,8-pentamethylnaphthalen-2-yl) ketone (Compound 16) and THF was added dropwise. The solution was stirred for 1 h at -78° C. and then diethyl chlorophosphate (3.27 mL, 22.6 mmol) was added. The dry-ice bath was removed, and the solution was allowed to warm to room temperature over 1 hour and added dropwise to a -78° C. solution of lithium diisopropylamide (43.1 mmol) and THF (82 mL) prepared as described above. The resultant mixture was warmed to room temperature over 3 hours and quenched with water. The products were extracted with hexanes, washed with 1N HCl, water, brine, dried (MgSO4) and concentrated under reduced pressure. The residue was purified by flash chromatography (SiO2, hexanes) to give the title compound as a colorless solid (4.3 g, 93%).

Workup

customThe dry-ice bath was removed
temperatureto warm to room temperature over 1 hour
customprepared
customquenched with water
extractionThe products were extracted with hexanes
washwashed with 1N HCl, water, brine
dry with materialdried (MgSO4)
concentrationconcentrated under reduced pressure
customThe residue was purified by flash chromatography (SiO2, hexanes)

Sources & evidence

ORD record: ord-a7044a61b0284c2a906fffb8dee0727d
Source dataset: uspto-grants-1995_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05475113

Reaction notes

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