ChemicalBook CAS DataBase List (E)-2-((3S,5R)-3,5-bis((tert-butyldimethylsilyl)oxy)-2-methylenecyclohexylidene)ethan-1-ol

(E)-2-((3S,5R)-3,5-bis((tert-butyldimethylsilyl)oxy)-2-methylenecyclohexylidene)ethan-1-ol synthesis

11synthesis methods

Product Name:(E)-2-((3S,5R)-3,5-bis((tert-butyldimethylsilyl)oxy)-2-methylenecyclohexylidene)ethan-1-ol
CAS Number:227961-42-4
Molecular formula:C21H42O3Si2
Molecular Weight:398.73

Ethanol, 2-[(3S,5R)-3,5-bis[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-methylenecyclohexylidene]-, 1-acetate, (2E)-

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(E)-2-((3S,5R)-3,5-bis((tert-butyldimethylsilyl)oxy)-2-methylenecyclohexylidene)ethan-1-ol

227961-42-4
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Yield:227961-42-4 201 mg

Reaction Conditions:

with methanol;potassium carbonate in dichloromethane at 20; for 0.5 h;Inert atmosphere;

Steps:

4.3.1 (E)-2-[(3S,5R)-3,5-Bis{(tert-butyldimethylsilyl)oxy}-2-methylenecyclohexylidene]ethan-1-ol (21)

To a solution of 20 (470 mg, 1.18 mmol) in CH₂Cl₂ (5 mL) were added triethylamine (329 μL, 2.36 mmol), acetic anhydride (181 μL, 1.77 mmol), and then dimethylaminopyridine (7.2 mg, 0.059 mmol) at 0 °C and stirred at room temperature for 45 min. After the reaction was quenched by NH₄Cl at 0 °C, the mixture was extracted with AcOEt, washed with brine, dried over Na₂SO₄, filtered and concentrated. The residue was purified by short column chromatography on neutral silica gel (hexane/AcOEt=50/1-10/1) to give a crude product, which was used without further separation. To a solution of a part of the above product (21 mg, 0.0476 mmol) in dry THF (2 mL) were added triethylamine (100 μL, 0.714 mmol), triphenylphosphine (12.5 mg, 0.0476 mmol), and then Pd(OAc)₂ (5.3 mg, 0.0238 mmol) at room temperature, and stirred at 50 °C. After 24 h, the reaction mixture was concentrated, and the residue was purified by short column chromatography on neutral silica gel (hexane/AcOEt=50/1-40/1) to give a crude product, which was used without further separation. To a solution of a part of the product (10.5 mg, 0.0238 mmol) in CH₂Cl₂ (1 mL) and MeOH (1 mL) were added K₂CO₃ (7 mg, 0.036 mmol) at 0 °C and stirred at room temperature for 30 min. After the reaction was quenched by NH₄Cl at 0 °C, the mixture was extracted with AcOEt, washed with brine, dried over Na₂SO₄, filtered and concentrated. The residue was purified by flash column chromatography on silica gel (hexane/AcOEt=10/1-8/1) to give 21¹⁶ (201 mg, 88% in 2 steps) as a colorless oil.

References:

Sawada, Daisuke;Kakuda, Shinji;Kamimura-Takimoto, Midori;Takeuchi, Akiko;Matsumoto, Yotaro;Kittaka, Atsushi [Tetrahedron,2016,vol. 72,# 22,p. 2838 - 2848]