Tetrahydro-4H-pyran-4-one → 4-(Methoxymethylidene)oxane

To a stirred suspension of (methoxymethyl)triphenyl-phosphonium chloride (24.82 g, 72.41 mmol) in THF (250 mL) cooled in an ice-water bath was added n-BuLi (24.76 mL or 2.42 M solution in hexane, 59.93 mmol). The reaction mixture was allowed to warm to room temperature for 1 h and then recooled in an ice-water bath and a solution of tetrahydro-4H-pyran-4-one (5.00 g, 49.94 mmol) in THF (10 mL) added. After 20 min the reaction mixture was concentrated to an oily reside, the residue was triturated with Et2O (150 mL), and the supernatant was decanted. This process was repeated (6×75 mL), and the combined supernatants were concentrated to give crude title compound (7.3 g) as an orange oil. Flash chromatography (10×18 cm) eluting with a gradient (5-10%) of EtOAc/hexane gave the title compound (2.25 g, 35%) as a volatile, colorless oil. TLC: Rf 0.13 (5:95 EtOAc:hexane). 1H NMR: δ5.85 (s, 1H, vinyl), 3.69-3.61 (m, 4H, CH2OCH2), 3.56 (s, 3H, OCH3), 2.32 and 2.06 (pr t, 4H, 2×CH2).

1. temperaturecooled in an ice-water bath
2. customrecooled in an ice-water bath
3. concentrationAfter 20 min the reaction mixture was concentrated to an oily reside
4. customthe residue was triturated with Et2O (150 mL)
5. customthe supernatant was decanted
6. concentrationthe combined supernatants were concentrated
7. customto give crude title compound (7.3 g) as an orange oil
8. washFlash chromatography (10×18 cm) eluting with a gradient (5-10%) of EtOAc/hexane

ORD record

ord-060e6f872d034f03980d8863f22bbcef

Source dataset

uspto-grants-2001_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06265381B1