Pyridine → (S)-(+)-6-benzyloxy-2,5,7,8-tetramethylchroman-2-carboxaldehyde

HRID 26663Notes

Reaction equation

HRID 26663 reaction equation
C(Cl)Cl.N1C=CC=CC=1.[CH2:10]([O:17][C:18]1[C:19]([CH3:33])=[C:20]2[C:25](=[C:26]([CH3:29])[C:27]=1[CH3:28])[O:24][C@:23]([CH3:32])([CH2:30][OH:31])[CH2:22][CH2:21]2)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1>C(Cl)(Cl)Cl>[CH2:10]([O:17][C:18]1[C:19]([CH3:33])=[C:20]2[C:25](=[C:26]([CH3:29])[C:27]=1[CH3:28])[O:24][C@:23]([CH3:32])([CH:30]=[O:31])[CH2:22][CH2:21]2)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1

Participants

5

Reactant 3

HCID 1049PyridineHCID 6344Dichloromethane2×HCID 10520197(S)-(-)-6-benzyloxy-2,5,7,8-tetramethylchroman-2-methanol

Product 1

HCID 10711117(S)-(+)-6-benzyloxy-2,5,7,8-tetramethylchroman-2-carboxaldehyde

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

To a stirred mixture of 36 ml. of dry CH2Cl2, 2.8 ml. of dry pyridine and 1.46 g. (14.6 mmol) of CrO3 was added a solution of 645 mg. (1.98 mmol) of (S)-(-)-6-benzyloxy-2,5,7,8-tetramethylchroman-2-methanol in 5 ml. of CH2Cl2. The dark mixture was stirred for 40 min. at room temperature then the organic solution was decanted and the dark residue was washed with ether and CH2Cl2. The combined organic solutions were diluted with ether, washed with 1 N NaOH, H2O and 1 N HCl and work-up was then completed in the usual manner. The yellow oily product (590 mg.) was chromatographed on 50 g. of silica gel. Elution with 19:1 (parts by volume) hexane-ether gave 492 mg. (76.7%) of pure (S)-(+)-6-benzyloxy-2,5,7,8-tetramethylchroman-2-carboxyaldehyde as an oil which crystallized yielding a colorless solid, mp 56°-58°;[α]25D+ 11.89° (c 5.2, CHCl3).

Workup

  1. additionTo a stirred mixture of 36 ml
  2. customthe organic solution was decanted
  3. washthe dark residue was washed with ether and CH2Cl2
  4. additionThe combined organic solutions were diluted with ether
  5. washwashed with 1 N NaOH, H2O and 1 N HCl
  6. customThe yellow oily product (590 mg.) was chromatographed on 50 g
  7. washElution with 19:1 (parts by volume) hexane-ether
  8. customgave 492 mg
  9. custom(76.7%) of pure (S)-(+)-6-benzyloxy-2,5,7,8-tetramethylchroman-2-carboxyaldehyde as an oil which crystallized
  10. customyielding a colorless solid, mp 56°-58°

Sources & evidence

ORD record
ord-7651463fa2e041ed84ab75cf8c2695cd
Source dataset
uspto-grants-1979_04
Patent number
US04151177

Reaction notes

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