ChemicalBook CAS DataBase List (R)-(-)-PENTEN-2-OL

(R)-(-)-PENTEN-2-OL synthesis

12synthesis methods

Product Name:(R)-(-)-PENTEN-2-OL
CAS Number:64584-92-5
Molecular formula:C5H10O
Molecular Weight:86.13

85116-38-7
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75-07-0 Synthesis

75-07-0
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64584-92-5
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$21.00/100mg

Yield: 77%

Reaction Conditions:

Stage #1:(+)-diisopinocampheylallylborane;acetaldehyde in diethyl ether at -78; for 1 h;
Stage #2: with dihydrogen peroxide;sodium hydroxide in diethyl ether;water at 25; for 2 h;

Steps:

1 4.1.1 (R)-Pent-4-en-2-ol 5
General procedure: To a stirred solution of (-)-Ipc₂B(allyl)borane (150 mmol) in dry Et₂O (200 mL) at -78 °C was added a solution of acetaldehyde (6 g, 136.4 mmol) in dry Et₂O (20 ml). The reaction mixture was stirred at -78 °C for 1 h, after which 3 M NaOH (111 mL, 330 mmol) and 30% H₂O₂ (45 mL) were added to the reaction mixture and the contents were stirred at 25 °C for an additional 2 h. After completion of the reaction (monitored by TLC), the organic layer was separated and the aqueous layer extracted with Et₂O, washed with brine, and dried over anhydrous Na₂SO₄. After removal of solvent the residue was distilled (bp 115 °C) to give (R)-(-)-4-penten-2-ol 5 (9.0 g) as a colorless liquid. Yield: 77%; [α]25D-9.67 [α]D25-9.67 (c 3.0, Et₂O) {lit.^7b [α]25D-9.84 [α]D25-9.84 (c 3.1, Et₂O)}; IR (CHCl₃): υ_max 3409, 3078, 2931, 2975, 1562, 1457, 1432, 1243, 1071, 914 cm^-1; ¹H NMR (200 MHz, CDCl₃): δ 1.19 (d, J = 6.0 Hz, 3H), 1.97 (br s, 1H), 2.14-2.26 (m, 2H), 3.83-3.84 (m, 1H), 5.10-5.14 (m, 2H), 5.76-5.87 (m, 1H); ¹³C NMR (50 MHz, CDCl₃): δ 22.7, 43.7, 66.8, 117.9, 134.8; Anal. Calcd for C₅H₁₀O requires C, 69.72; H, 11.70. Found: C, 69.63; H, 11.78%.