Methanol → Methyl cis-7-bromo-5-heptenoate

HRID 2351799Notes

Reaction equation

HRID 2351799 reaction equation
O[CH2:2]/[CH:3]=[CH:4]\[CH2:5][CH2:6][CH2:7][C:8]([O:10][CH3:11])=[O:9].C(Br)(Br)(Br)[Br:13].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.CO>C(Cl)Cl>[Br:13][CH2:2]/[CH:3]=[CH:4]\[CH2:5][CH2:6][CH2:7][C:8]([O:10][CH3:11])=[O:9]

Participants

6

Reactant 4

HCID 887MethanolHCID 11205Carbon tetrabromideHCID 11776TriphenylphosphineHCID 15586879Methyl cis-7-Hydroxy-5-heptenoate

Product 1

HCID 11253002Methyl cis-7-bromo-5-heptenoateYield 96%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of alcohol 39 (1.48 g, 9.36 mmol) and carbon tetrabromide (3.40 g, 10.25 mmol) in dry CH2Cl2 (50 mL) was added triphenylphosphine (2.70 g, 10.30 mmol) in portions. The reaction mixture was stirred for 40 min and MeOH (1 mL) was added. Concentration on a rotary evaporator, followed by flash chromatography using 50:1 hexane/EtOAc as eluent, gave 40 as a colorless oil (1.98 g, 96%): IR (neat) 3020 (w), 2945, 2860 (w), 1740 (s), 1435, 1370, 1200, 1165 cm-1 ; 1H NMR (CDCl3) δ 5.77 (m, J1 =10.5 Hz, J2 =8.3 Hz, J3 =1.4 Hz, 1H), 5.56 (m, J1 =10.6 Hz, J2 =7.5 Hz, 1H), 3.98 (d, J=8.1 Hz, 2H), 3.67 (s, 3H), 2.34 (t, J=7.4 Hz, 2H), 2.19 (dq, J1 =7.5 Hz, J2 =1.4 Hz, 2H), 1.74 (p. J=7.3 Hz, 2H); 13C NMR (CDCl3) δ 173.55, 134.48, 126.26, 51.37, 33.06, 26.60, 26.01, 24.28. A minor amount (ca. 5%) of methyl trans-7-bromo-5-heptenoate could be seen in the 1H NMR spectrum at δ 3.93.

Workup

  1. concentrationConcentration
  2. customon a rotary evaporator

Sources & evidence

ORD record
ord-7b5c072b37aa4053ab87a7cc86c2a287
Source dataset
uspto-grants-1989_10
Patent number
US04873360

Reaction notes

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