반응 #489982

반응 방정식

NaOH

HCl

Dess-Martin periodinane

BH3-THF

2,2-Dimethyl-3,4-dihydro-2H-chromene-8-carboxylic acid

→

desired product

2,2-dimethyl-3,4-dihydro-2H-chromene-8-carbaldehyde

용매

dichloromethane

THF

반응 조건

후처리

1. 1
   온도The mixture was again heated at 65° C. for 30 minutes
2. 2
   온도The solution was cooled to room temperature
3. 3
   추출extracted with EtOAc (40.0 mL, 3×)
4. 4
   건조The combined organic layers were dried over Na2SO4
5. 5
   여과filtered
6. 6
   농축concentrated under vacuum
7. 7
   기타to obtain the crude alcohol as a colorless oil, which
8. 8
   workup.STIRRINGThe reaction mixture was stirred for 1 hour at room temperature
9. 9
   농축concentrated under vacuum on silica gel
10. 10
    기타The crude residue was purified by silica gel chromatography
11. 11
    세척eluting with 0-15% EtOAc/hexanes

실험 절차

2,2-Dimethyl-3,4-dihydro-2H-chromene-8-carboxylic acid (300 mg, 1.45 mmol) dissolved in THF (3.60 mL) was cooled to 0° C. and BH3-THF (5.82 mL, 5.82 mmol) was added dropwise via a syringe. The resulting solution was stirred at 65° C. for 1 hour, and then allowed to cool to room temperature before addition of 6 N HCl (2.50 mL). The mixture was again heated at 65° C. for 30 minutes. The solution was cooled to room temperature, made basic with 1N NaOH and extracted with EtOAc (40.0 mL, 3×). The combined organic layers were dried over Na2SO4, filtered and concentrated under vacuum to obtain the crude alcohol as a colorless oil, which was directly used to the next step. The crude alcohol was dissolved in dichloromethane (5.00 mL), and Dess-Martin periodinane (1.23 g, 2.91 mmol) was added in one portion at room temperature. The reaction mixture was stirred for 1 hour at room temperature and concentrated under vacuum on silica gel. The crude residue was purified by silica gel chromatography eluting with 0-15% EtOAc/hexanes to give the desired product as a colorless oil.

출처