18-Crown-6 → (E)-2-iodo-1-methyl-4-(2-(2,6,6-trimethylcyclohex-1-enyl)vinyl)benzene

HRID 242722

Reaction equation

[Br-].C1([P+](C2C=CC=CC=2)(C2C=CC=CC=2)[CH2:9][C:10]2[C:15]([CH3:17])([CH3:16])[CH2:14][CH2:13][CH2:12][C:11]=2[CH3:18])C=CC=CC=1.C1OCCOCCOCCOCCOCCOC1.CC(C)([O-])C.[K+].[I:55][C:56]1[CH:57]=[C:58]([CH:61]=[CH:62][C:63]=1[CH3:64])[CH:59]=O.[PH4+]>C(Cl)Cl>[I:55][C:56]1[CH:57]=[C:58](/[CH:59]=[CH:9]/[C:10]2[C:15]([CH3:16])([CH3:17])[CH2:14][CH2:13][CH2:12][C:11]=2[CH3:18])[CH:61]=[CH:62][C:63]=1[CH3:64]

Participants

Conditions

Temperature: -78 °C

Procedure

To a −78° C. solution of triphenyl((2,6,6-trimethylcyclohex-1-enyl)methyl)phosphonium bromide (24) (0.3787 g, 0.79 mmol) and 18-crown-6 (0.0246 g, 0.093 mmol) in CH2Cl2 (7 mL) was added potassium tert-butoxide (0.0991 g, 0.88 mmol). The mixture was sonicated at room temperature under argon for 2 min, resulting in a deep red solution. The mixture was cooled to −78° C. then a solution of 3-iodo-4-methylbenzaldehyde (0.1742 g, 0.71 mmol) in CH2Cl2 (3 mL+2 mL) was added and stirred for 5 min. The reaction mixture was allowed to warm to room temperature. Additional phosphonium salt 24 (0.3725 g, 1.6 mmol), 3-iodo-4-methylbenzaldehyde (0.2538 g, 1.7 mmol) and potassium tert-butoxide (0.1548 g, 1.38 mmol) were then added and the reaction was stirred at room temperature for 4.3 h. The reaction was partitioned between EtOAc and water then the combined organics were washed with brine, dried over MgSO4 and concentrated under reduced pressure. Purification by flash chromatography (6 to 50% EtOAc-hexanes gradient) gave (E)-2-iodo-1-methyl-4-(2-(2,6,6-trimethylcyclohex-1-enyl)vinyl)benzene as a white solid. Yield (0.26 g, 45%): 1H NMR (400 MHz, DMSO-d6) δ 7.91 (d, J=1.6 Hz, 1H), 7.44 (dd, J=7.6, 1.2 Hz, 1H), 7.29 (d, J=7.2 Hz, 1H), 6.71 (d, J=16.4 Hz, 1H), 6.28 (6, J=16.8 Hz, 1H), 2.35 (s, 3H), 2.01 (t, J=6.4 Hz, 2H), 1.72 (s, 3H), 1.57-1.64 (m, 2H), 1.43-1.47 (m, 2H), 1.04 (s, 6H).

Workup

customThe mixture was sonicated at room temperature under argon for 2 min
customresulting in a deep red solution
temperatureto warm to room temperature
stirringthe reaction was stirred at room temperature for 4.3 h
customThe reaction was partitioned between EtOAc and water
washthe combined organics were washed with brine
dry with materialdried over MgSO4
concentrationconcentrated under reduced pressure
customPurification by flash chromatography (6 to 50% EtOAc-hexanes gradient)

Sources & evidence

ORD record: ord-5f33ccf406034e1dbb379159b510b051
Source dataset: uspto-grants-2014_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08653142B2

Linked notes

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