Benzene → Benzyl 9-oxo-3-azaspiro(5.5)undec-7-ene-3-carboxylate

HRID 2274971Notes

Reaction equation

HRID 2274971 reaction equation
[CH:1]([CH:3]1[CH2:8][CH2:7][N:6]([C:9]([O:11][CH2:12][C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)=[O:10])[CH2:5][CH2:4]1)=O.O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C1C=CC=CC=1.[CH3:37][C:38](=[O:41])[CH:39]=[CH2:40]>>[O:41]=[C:38]1[CH2:39][CH2:40][C:3]2([CH2:8][CH2:7][N:6]([C:9]([O:11][CH2:12][C:13]3[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=3)=[O:10])[CH2:5][CH2:4]2)[CH:1]=[CH:37]1

Participants

5

Reactant 4

HCID 241BenzeneHCID 6570Methyl vinyl ketoneHCID 521998p-Toluenesulfonic acid monohydrateHCID 2776272Benzyl 4-formylpiperidine-1-carboxylate

Product 1

HCID 23435732Benzyl 9-oxo-3-azaspiro(5.5)undec-7-ene-3-carboxylateYield 57.2%

Procedure

Benzyl 4-formylpiperidine-1-carboxylate (5.17 g, 20.907 mmol) and p-Toluenesulfonic acid monohydrate (0.398 g, 2.091 mmol) were stirred in Benzene (30.0 ml, 334.136 mmol) at 70° C. But-3-en-2-one (3.76 ml, 41.813 mmol) was added and the reaction mixture was refluxed o/n while removing water with dean-stark trap. After cooling the reaction mixture to rt, sat. NaHCO3 soln. was added and the organic layer was dried over Na2SO4 and evaporated. The resulting oil was purified by Biotage (SiO2, 250 g, EtOAc/Hep 10% to 50%) to afford the title compound (3.58 g, 11.96 mmol, 57.2% yield).

Workup

  1. temperaturethe reaction mixture was refluxed o/n
  2. customwhile removing water with dean-stark trap
  3. additionwas added
  4. dry with materialthe organic layer was dried over Na2SO4
  5. customevaporated
  6. customThe resulting oil was purified by Biotage (SiO2, 250 g, EtOAc/Hep 10% to 50%)

Sources & evidence

ORD record
ord-24173da873b440488f373cb24b05c467
Source dataset
uspto-grants-2015_09
Patent number
US09126999B2

Reaction notes

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