Diisobutylaluminum hydride → 2,2-Dimethylspiro[chroman-4,1'-cyclopropane]-6-carbaldehyde

HRID 402797Notes

Reaction equation

HRID 402797 reaction equation
[CH3:1][C:2]1([CH3:18])[CH2:13][C:10]2([CH2:12][CH2:11]2)[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:14](OC)=[O:15])[CH:8]=2)[O:3]1.CC(C[AlH]CC(C)C)C.CC(OI1(OC(C)=O)(OC(C)=O)OC(=O)C2C=CC=CC1=2)=O>C1(C)C=CC=CC=1.ClCCl>[CH3:1][C:2]1([CH3:18])[CH2:13][C:10]2([CH2:11][CH2:12]2)[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([CH:14]=[O:15])[CH:8]=2)[O:3]1

Participants

6

Reactant 3

HCID 14487Diisobutylaluminum hydrideHCID 159087TriacetoxyperiodinaneHCID 67471307Spiro[4H-1-benzopyran-4,1′-cyclopropane]-6-carboxylic acid, 2,3-dihydro-2,2-dimethyl-, methyl ester

Product 1

HCID 874117612,2-Dimethylspiro[chroman-4,1'-cyclopropane]-6-carbaldehyde

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
-78 °C

Procedure

Methyl 2,2-dimethyl-2,3-dihydrospiro[chromene-4,1′-cyclopropane]-6-carboxylate (33.0 mg, 0.13 mmol) was dissolved in dry toluene (1.34 mL), and cooled to −78° C. DIBAL-H (536 μL, 0.54 mmol) was added dropwise via a syringe. The reaction mixture was stirred for 2 hours at −78° C. It was then quenched with methanol (500 μL) at the same temperature, and diluted with EtOAc (15.0 mL). The organic layer was washed with water (10.0 mL), dried over Na2SO4, filtered and concentrated under vacuum to afford the crude alcohol, which was used directly to the next step. The crude alcohol was dissolved in dichloromethane (4.00 mL) and Dess-Martin periodinane (114 mg, 0.27 mmol) was added in one portion at room temperature. The resulting mixture was stirred at room temperature for 1 hour and concentrated under vacuum on silica gel. It was then purified by silica gel chromatography eluting with 0-15% EtOAc/hexanes to give the desired product as a colorless oil.

Workup

  1. customIt was then quenched with methanol (500 μL) at the same temperature
  2. additiondiluted with EtOAc (15.0 mL)
  3. washThe organic layer was washed with water (10.0 mL)
  4. dry with materialdried over Na2SO4
  5. filtrationfiltered
  6. concentrationconcentrated under vacuum
  7. customto afford the crude alcohol, which
  8. stirringThe resulting mixture was stirred at room temperature for 1 hour
  9. concentrationconcentrated under vacuum on silica gel
  10. customIt was then purified by silica gel chromatography
  11. washeluting with 0-15% EtOAc/hexanes

Sources & evidence

ORD record
ord-4294b7c667fe4359b8aa8f031d421810
Source dataset
uspto-grants-2014_06
Patent number
US08742110B2

Reaction notes

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