4-(methoxymethylidene)oxane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred suspension of (methoxymethyl)triphenylphosphonium 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 2.42M 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: δ 5.85 (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). cooled in an ice-water bath recooled in an ice-water bath After 20 min the reaction mixture was concentrated to an oily reside the residue was triturated with Et2O (150 mL) the supernatant was decanted 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

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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). cooled in an ice-water bath recooled in an ice-water bath After 20 min the reaction mixture was concentrated to an oily reside the residue was triturated with Et2O (150 mL) the supernatant was decanted 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

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Tetrahydro-4H-pyran-4-one (5.00 g, 50 mmol) was dissolved in tetrahydrofuran (250 ml) and cooled in an ice-water bath. To this solution was added n-butyl lithium (24 ml of a 2.5M solution in hexane, 60 mmol) and the reaction mixture was then allowed to warm to room temperature and stirred for 1 hour. This was then cooled to 0° C. and a solution of (methoxymethyl)triphenyl phosphonium chloride (25.6 g, 75 mmol) in tetrahydrofuran (10 ml) was added and the reaction stirred for 30 minutes. The reaction mixture was then concentrated under reduced pressure and the residue triturated with diethyl ether (10×), decanting the supernatant each time. The combined supernatants were then evaporated under reduced pressure. The residue was purified by column chromatography on silica gel using an elution gradient of pentane:ethyl acetate (95:5 to 90:10) to provide the title compound, 1.80 g. cooled in an ice-water bath This was then cooled to 0° C. the reaction stirred for 30 minutes The reaction mixture was then concentrated under reduced pressure the residue triturated with diethyl ether (10×) decanting the supernatant each time The combined supernatants were then evaporated under reduced pressure The residue was purified by column chromatography on silica gel using an elution gradient of pentane:ethyl acetate (95:5 to 90:10)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred suspension of (methoxymethyl)triphenylphosphonium 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 2.42M 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: δ 5.85 (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). cooled in an ice-water bath recooled in an ice-water bath After 20 min the reaction mixture was concentrated to an oily reside the residue was triturated with Et2O (150 mL) the supernatant was decanted 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