Benzene → (-)-(10R)-3,3,8,8,10-Pentamethyl-1,5-dioxaspiro[5,5]undecan-9-one

HRID 440224

反応式

HRID 440224 の反応式
[CH3:1][C:2]1([CH3:11])[CH2:7][C:6](=[O:8])[CH2:5][C@@H:4]([CH3:9])[C:3]1=[O:10].[CH3:12][C:13]([CH3:18])([CH2:16]O)[CH2:14][OH:15].C1C=CC=CC=1>O>[CH3:12][C:13]1([CH3:18])[CH2:14][O:15][C:6]2([CH2:5][C@@H:4]([CH3:9])[C:3](=[O:10])[C:2]([CH3:1])([CH3:11])[CH2:7]2)[O:8][CH2:16]1

参加物

5

反応物 3

HCID 241BenzeneHCID 31344Neopentyl glycolHCID 10176229Levodione

生成物 1

HCID 14702805(-)-(10R)-3,3,8,8,10-Pentamethyl-1,5-dioxaspiro[5,5]undecan-9-one収率 99.2%

試薬・触媒・溶媒 1

HCID 962Water溶媒

実験手順

A mixture of (-)-(6R)-2,2,6-trimethyl-1,4-cyclohexandione (924 mg, 6.0 mmol), 2,2-dimethyl-1,3-propandiol (791 mg, 7.6 mmol), pyridinium p-tosylate (34 mg, 0.13 mmol), and benzene (15 mL) was heated to reflux under a Dean-Stark water separator for 4 h. The reaction mixture was allowed to cool to room temperature before it was washed with H2O, and dried over anhydrous Na2SO4. Evaporation of solvent gave a pale yellow oil (1.43 g) as the crude product, which was distilled using the Kugel-rohr apparatus (80°-100° C., 0.03 mm Hg) to give pure ketal as a colorless oil (1.31 g, 91%), [a]D -87.7° C. (c 1.10, CH3OH); ir: 1710 cm-1; 1H nmr d: 0.85 (s, 3H, CH3), 0.91 (d, J=6.6 Hz, 3H, CHCH3), 0.97 (s, 6H, 2 CH3), 1.16 (s, 3H, CH3), 1.56 (dd, J=13.5, 13.5 Hz, H-11ax), 1.58 (d, J=14.2 Hz, H-7ax), 2.38 (ddd, J=13.5, 5.3, 3.8 Hz, 1H, H-11eq), 2.47 (dd, J=14.2, 3.8 Hz, 1H, H-7eq), 2.85 (m, 1H, CHCH3), 3.41 and 3.48 (2dd, J=11.4, 1.6 Hz, 2H, 2 equatorial H at C2 and C4), 3.53 and 3.61 (2d, J=11.4 Hz, 2H, 2 axial H at C2 and C4); ms m/e: 240 (M+, 0.58), 141 (27), 155 (98), 83 (27), 69 (100).

後処理

  1. temperaturewas heated
  2. washwas washed with H2O
  3. dry with materialdried over anhydrous Na2SO4
  4. customEvaporation of solvent

出典と根拠

ORDレコード
ord-395accb4eeab49f7ac2765bc38355677
出典データセット
uspto-grants-1996_05
特許番号
US05518995

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