Boron trifluoride → (Z)-(5R)-9-(tetrahydro-pyran-2-yloxy)-1-trimethylsilanyl-non-2-en-7-yn-5-ol

HRID 1604843Notes

Reaction equation

HRID 1604843 reaction equation
[CH2:1]([O:4][CH:5]1[CH2:10][CH2:9][CH2:8][CH2:7][O:6]1)[C:2]#[CH:3].[Li]CCCC.B(F)(F)F.[CH3:20][Si:21]([CH3:30])([CH3:29])[CH2:22]/[CH:23]=[CH:24]\[CH2:25][C@@H:26]1[CH2:28][O:27]1>C1COCC1>[O:6]1[CH2:7][CH2:8][CH2:9][CH2:10][CH:5]1[O:4][CH2:1][C:2]#[C:3][CH2:28][C@H:26]([OH:27])[CH2:25]/[CH:24]=[CH:23]\[CH2:22][Si:21]([CH3:30])([CH3:20])[CH3:29]

Participants

6

Reactant 4

HCID 6356Boron trifluorideHCID 98609Tetrahydro-2-(2-propynyloxy)-2H-pyranHCID 86754182(Z)-(R)-trimethyl-(4-oxiranyl-but-2-enyl)silaneHCID 178418339Butyllithium

Product 1

HCID 70003429(Z)-(5R)-9-(tetrahydro-pyran-2-yloxy)-1-trimethylsilanyl-non-2-en-7-yn-5-olYield 93.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

24.5 ml (174 mmol) of Tetrahydro-2-(2-propynyloxy)2H-pyran was dissolved in 285 ml of abs. THF and deprotonated at -13°--6° by adding slowly 112 ml of nBuLi (1.55 M, hexane). 20 Minutes later, the solution was cooled to -75° and 21.85 ml of BF3 oEtOEt was added. Afterwards, 10.51 g of (Z)-(R)-trimethyl-(4-oxiranyl-but-2-enyl)-silane, dissolved in 96 ml of abs. THF, was added within 75 minutes while maintaining the temperature below -70°. The reaction mixture was kept for another 50 minutes at this temperature and then poured onto crushed ice/NaHCO3, extracted with ether, washed with brine, dried over sodium sulfate and evaporated to dryness. Flash chromatography (SiO2, hexane/AcOEt=8/2) produced 17.83 g of (Z)-(5R)-9-(tetrahydro-pyran-2-yloxy)-1-trimethylsilanyl-non-2-en-7-yn-5-ol as colorless oil (1:1 epimeric mixture).

Workup

  1. customdeprotonated at -13°--6°
  2. temperature20 Minutes later, the solution was cooled to -75°
  3. temperaturewhile maintaining the temperature below -70°
  4. additionpoured
  5. extractionextracted with ether
  6. washwashed with brine
  7. dry with materialdried over sodium sulfate
  8. customevaporated to dryness

Sources & evidence

ORD record
ord-da73cceb85f8412c9db993c343aa86b0
Source dataset
uspto-grants-1999_11
Patent number
US05994569

Reaction notes

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