Sodium borohydride → methyl 1-(3,4-dihydro-2H-chromen-6-yl)cyclopropane-1-carboxylate

HRID 1964248Notes

Reaction equation

HRID 1964248 reaction equation
[BH4-].[Na+].[CH3:3][O:4][C:5]([C:7]1([C:10]2[CH:11]=[C:12]3[C:17](=[CH:18][CH:19]=2)[O:16][CH2:15][CH2:14][C:13]3=O)[CH2:9][CH2:8]1)=[O:6]>FC(F)(F)C(O)=O>[CH3:3][O:4][C:5]([C:7]1([C:10]2[CH:11]=[C:12]3[C:17](=[CH:18][CH:19]=2)[O:16][CH2:15][CH2:14][CH2:13]3)[CH2:8][CH2:9]1)=[O:6]

Participants

4

Reactant 2

HCID 4311764Sodium borohydrideHCID 59129225Methyl 1-(4-oxochroman-6-yl)cyclopropanecarboxylate

Product 1

HCID 59129159methyl 1-(3,4-dihydro-2H-chromen-6-yl)cyclopropane-1-carboxylateYield 92.7%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidSolvent

Procedure

To trifluoroacetic acid (20 mL) was added NaBH4 (0.70 g, 130 mmol) in portions at 0° C. under N2 atmosphere. After stirring for 5 min, a solution of 1-(4-oxo-chroman-6-yl)-cyclopropanecarboxylic methyl ester (1.6 g, 6.5 mmol) was added at 15° C. The reaction mixture was stirred for 1 h at room temperature before being slowly quenched with water. The resulting mixture was extracted with EtOAc (50 mL×3). The combined organic extracts dried over anhydrous Na2SO4 and evaporated under vacuum to give 1-chroman-6-yl-cyclopropanecarboxylic methyl ester (1.4 g, 92%), which was used directly in the next step. 1H NMR (300 MHz, CDCl3) δ 7.07-7.00 (m, 2 H), 6.73 (d, J=8.4 Hz, 1 H), 4.17 (t, J=5.1 Hz, 2 H), 3.62 (s, 3 H), 2.79-2.75 (m, 2 H), 2.05-1.96 (m, 2 H), 1.57-1.54 (m, 2 H), 1.16-1.13 (m, 2H).

Workup

  1. stirringThe reaction mixture was stirred for 1 h at room temperature
  2. custombefore being slowly quenched with water
  3. extractionThe resulting mixture was extracted with EtOAc (50 mL×3)
  4. dry with materialThe combined organic extracts dried over anhydrous Na2SO4
  5. customevaporated under vacuum

Sources & evidence

ORD record
ord-aa9696ddcf884c6c83ee796e0548f6d7
Source dataset
uspto-grants-2013_04
Patent number
US08415387B2

Reaction notes

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