(R)-2-Methyl-CBS-oxazaborolidine → (S)-2-(4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl)-1-cyclopentenyl-1-hydroxyethane

HRID 260124

反応式

HRID 260124 の反応式
[CH:1]1([C:6]([CH2:8][C:9]2[C:10]([O:22][Si:23]([C:26]([CH3:29])([CH3:28])[CH3:27])([CH3:25])[CH3:24])=[C:11]3[C:15](=[C:16]([CH3:20])[C:17]=2[CH2:18][CH3:19])[CH2:14][O:13][C:12]3=[O:21])=[O:7])[CH2:5][CH2:4][CH2:3][CH2:2]1.CB1N2CCC[C@@H]2C(C2C=CC=CC=2)(C2C=CC=CC=2)O1>C1(C)C=CC=CC=1>[Si:23]([O:22][C:10]1[C:9]([CH2:8][C@@H:6]([C:1]2[CH2:5][CH2:4][CH2:3][CH:2]=2)[OH:7])=[C:17]([CH2:18][CH3:19])[C:16]([CH3:20])=[C:15]2[C:11]=1[C:12](=[O:21])[O:13][CH2:14]2)([C:26]([CH3:27])([CH3:28])[CH3:29])([CH3:25])[CH3:24]

参加物

4

反応物 2

HCID 9838490(R)-2-Methyl-CBS-oxazaborolidineHCID 53886302Cyclopentyl (4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl methyl)methanone

生成物 1

HCID 70213482(S)-2-(4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl)-1-cyclopentenyl-1-hydroxyethane

試薬・触媒・溶媒 1

HCID 1140Toluene溶媒

反応条件

温度
-30 °C

実験手順

Cyclopentyl (4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl methyl)methanone (4.2 g) was treated with a 1M toluene solution of (R)-tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrolo-[1,2-c][1,3,2]oxazaborole (3 ml). The toluene was evaporated in vacuo and methylene chloride added (2 ml). The reaction mixture was cooled to -30° C. and borane/dimethyl sulfide (0.33 ml) was added three times at 45 minute intervals. The reaction mixture was stirred 16 hours at -30° C. and quenched by addition of 1M hydrogen chloride/ether (3 ml). Toluene was added (10 ml) and the solution filtered, diluted with ether (200 ml), washed with aqueous hydrochloric acid, aqueous sodium bicarbonate and brine. Drying and evaporation gave an oil which was purified by silica gel chromatography to give (S)-2-(4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl)-1-cyclopentenyl-1-hydroxyethane. Further purification by crystallization from t-butylmethyl ether gave material with an enantiomeric excess of 97.8% (Chiracel OD-H, 85:15 hexane:i-propanol, 0.8 ml/minute, minor 8.3 minutes, major 9.2 minutes).

後処理

  1. customThe toluene was evaporated in vacuo and methylene chloride
  2. additionadded (2 ml)
  3. additionborane/dimethyl sulfide (0.33 ml) was added three times at 45 minute intervals
  4. customquenched by addition of 1M hydrogen chloride/ether (3 ml)
  5. additionToluene was added (10 ml)
  6. filtrationthe solution filtered
  7. additiondiluted with ether (200 ml)
  8. washwashed with aqueous hydrochloric acid, aqueous sodium bicarbonate and brine
  9. customDrying
  10. customevaporation
  11. customgave an oil which
  12. customwas purified by silica gel chromatography

出典と根拠

ORDレコード
ord-3e0a60fab889430b9a0f026dcb081e32
出典データセット
uspto-grants-1996_06
特許番号
US05525602

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