Hydrochloric Acid → 4-((tert-Butyl(dimethyl)silyl)oxy)cyclopent-2-en-1-one

HRID 2393880Notes

Reaction equation

HRID 2393880 reaction equation
[OH:1][CH:2]1[CH2:6][C:5](=[O:7])[CH:4]=[CH:3]1.C(N(CC)CC)C.[Si:15](Cl)([C:18]([CH3:21])([CH3:20])[CH3:19])([CH3:17])[CH3:16].Cl>O1CCCC1.CN(C)C1C=CN=CC=1>[O:7]([CH:5]1[CH2:6][C:2](=[O:1])[CH:3]=[CH:4]1)[Si:15]([C:18]([CH3:21])([CH3:20])[CH3:19])([CH3:17])[CH3:16]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 8471TriethylamineHCID 28928tert-Butyldimethylsilyl chlorideHCID 41691604-Hydroxycyclopent-2-en-1-one

Product 1

HCID 41316994-((tert-Butyl(dimethyl)silyl)oxy)cyclopent-2-en-1-oneYield 83.2%

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
0 °C

Procedure

A solution of 4-hydroxy-2-cyclopentenone (191 g, 1.95 mol, prepared in example 1) and triethylamine (430 mL, 3.09 mol) in anhydrous tetrahydrofuran (1 L) is treated with 4-dimethylaminopyridine (4.90 g, 40.0 mmol). The solution is cooled to 0° C. and treated portionwise, over 10 minutes, with tert-butyldimethylsilyl chloride (278 g, 1.84 mol) maintaining the temperature at or below 10° C. The reaction is then allowed to stir overnight at room temperature. It is then poured into aqueous HCl (0.5N, 1 L). The phases are separated and the aqueous phase is extracted with heptane (2×1 L). The organic phase and organic extracts are combined, washed with aqueous HCl (0.5N, 2×500 mL), then 5% sodium bicarbonate (500 mL), then brine (500 mL), dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum (40° C., 20 mmHg) to provide the title compound (325 g). This is purified by Kugelrohr distillation (70°-80° C., 1 mmHg) to provide the title compound (282 g, 72% yield) as a light yellow oil, Rf =0.55, 20% ethyl acetate/hexane, GC retention time is 14.97 minutes; 1H NMR (CDCl3) δ 7.48 (dd, J=5.7, 2.4 Hz, 1 H), 6.20 (d, J=5.7 Hz, 1 H), 4.95-4.99 (m, 1 H), 2.72 (dd, J=18.2, 6.0 Hz, 1 H), 2.25 (dd, J=18.2, 2.3 Hz, 1 H), 0.88 (s, 9 H), 0.11 (s, 6 H); 13 C NMR (CDCl3) δ 206.4, 163.8, 134.4, 70.8, 44.9, 25.7, 25.6, 18.0; IR (neat) νmax 2957, 2931, 2887, 2858, 1725 cm-1 ; MS (EI) m/e (% relative intensity) 212 (M+, 5), 155 (M+ -57, 100).

Workup

  1. temperaturemaintaining the temperature at or below 10° C
  2. customThe phases are separated
  3. extractionthe aqueous phase is extracted with heptane (2×1 L)
  4. washwashed with aqueous HCl (0.5N, 2×500 mL)
  5. dry with material5% sodium bicarbonate (500 mL), then brine (500 mL), dried over anhydrous magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated under vacuum (40° C., 20 mmHg)

Sources & evidence

ORD record
ord-19b4e8a51f1b48adb320567039291b6b
Source dataset
uspto-grants-1998_09
Patent number
US05808112

Reaction notes

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