cyclohexa-1,5-dien-1-yloxy(trimethyl)silane

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

Procedure: To stannous chloride (379 mg) was added a dichloromethane solution (10 ml) of chlorotrimethylsilane (217 mg) followed by addition of a dichloromethane solution (10 ml) of (3R,4R)-4-acetoxy-3-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1-trimethylsilylazetidin-2-one (7.19 g). To this suspension was added a dichloromethane solution (10 ml) of 2-[(trimethylsilyl)oxy]-1,3-cyclohexadiene (4.05 g) dropwise at room temperature over a period of 1 hour. The mixture was stirred at 25° C. for 2 hours, at the end of which time a dichloromethane solution (10 ml) of 2-[(trimethylsilyl)oxy]-1,3-cyclohexadiene (5.38 g) was added dropwise over a period of 1 hour. The mixture was further stirred for 5 hours and then allowed to stand at 0° C. overnight. The solvent was then distilled off under reduced pressure. To the residue were added ether (100 ml) and aqueous sodium hydrogen carbonate solution (30 ml) and the mixture was stirred for 10 minutes. The insolubles were filtered off and the aqueous layer was extracted with ether. The ether layer was washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was then distilled off under reduced pressure and the residue was dissolved in THF-water (17:2, 95 ml). To this solution was added pyridinium p-toluenesulfonate (610 mg) and the mixture was stirred at room temperature for 1 hour. The solvent was distilled off under reduced pressure and ether (150 ml) was added to the residue. The organic layer was washed successively with water and saturated sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was then distilled off under reduced pressure and the residue was purified by flash column chromatography (packing: silica gel 300 g; ether-hexane 5:1) to give (3S,4R)-3-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-4-[(R)-2-oxo-3-cyclohexen-1-yl]azetiidin-2-one (R-compound; 1.01 g) and (3S,4R)-3-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-4-[(S)-2-oxo-3-cyclohexen-1-yl]azetidin-2-one (S-compound; 0.96 g). was added dropwise over a period of 1 hour to stand at 0° C. overnight The solvent was then distilled off under reduced pressure To the residue were added ether (100 ml) and aqueous sodium hydrogen carbonate solution (30 ml) the mixture was stirred for 10 minutes The insolubles were filtered off the aqueous layer was extracted with ether The ether layer was washed with saturated aqueous sodium chloride solution dried over anhydrous sodium sulfate The solvent was then distilled off under reduced pressure the residue was dissolved in THF-water (17:2, 95 ml) To this solution was added pyridinium p-toluenesulfonate (610 mg) the mixture was stirred at room temperature for 1 hour The solvent was distilled off under reduced pressure and ether (150 ml) was added to the residue The organic layer was washed successively with water and saturated sodium chloride solution dried over anhydrous sodium sulfate The solvent was then distilled off under reduced pressure the residue was purified by flash column chromatography (packing: silica gel 300 g; ether-hexane 5:1)

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

Procedure: To stannous chloride (379 mg) was added a dichloromethane solution (10 ml) of chlorotrimethylsilane (217 mg) followed by addition of a dichloromethane solution (10 ml) of (3R,4R)-4-acetoxy-3-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-1-trimethylsilylazetidin-2-one (7.19 g). To this suspension was added a dichloromethane solution (10 ml) of 2-[(trimethylsilyl)oxy]-1,3-cyclohexadiene (4.05 g) dropwise at room temperature over a period of 1 hour. The mixture was stirred at 25° C. for 2 hours, at the end of which time a dichloromethane solution (10 ml) of 2-[(trimethylsilyl)oxy]-1,3-cyclohexadiene (5.38 g) was added dropwise over a period of 1 hour. The mixture was further stirred for 5 hours and then allowed to stand at 0° C. overnight. The solvent was then distilled off under reduced pressure. To the residue were added ether (100 ml) and aqueous sodium hydrogen carbonate solution (30 ml) and the mixture was stirred for 10 minutes. The insolubles were filtered off and the aqueous layer was extracted with ether. The ether layer was washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was then distilled off under reduced pressure and the residue was dissolved in THF-water (17:2, 95 ml). To this solution was added pyridinium p-toluenesulfonate (610 mg) and the mixture was stirred at room temperature for 1 hour. The solvent was distilled off under reduced pressure and ether (150 ml) was added to the residue. The organic layer was washed successively with water and saturated sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was then distilled off under reduced pressure and the residue was purified by flash column chromatography (packing: silica gel 300 g; ether-hexane 5:1) to give (3S,4R)-3-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-4-[(R)-2-oxo-3-cyclohexen-1-yl]azetiidin-2-one (R-compound; 1.01 g) and (3S,4R)-3-[(R)-1-[(tert-butyldimethylsilyl)oxy]ethyl]-4-[(S)-2-oxo-3-cyclohexen-1-yl]azetidin-2-one (S-compound; 0.96 g). was added dropwise over a period of 1 hour to stand at 0° C. overnight The solvent was then distilled off under reduced pressure To the residue were added ether (100 ml) and aqueous sodium hydrogen carbonate solution (30 ml) the mixture was stirred for 10 minutes The insolubles were filtered off the aqueous layer was extracted with ether The ether layer was washed with saturated aqueous sodium chloride solution dried over anhydrous sodium sulfate The solvent was then distilled off under reduced pressure the residue was dissolved in THF-water (17:2, 95 ml) To this solution was added pyridinium p-toluenesulfonate (610 mg) the mixture was stirred at room temperature for 1 hour The solvent was distilled off under reduced pressure and ether (150 ml) was added to the residue The organic layer was washed successively with water and saturated sodium chloride solution dried over anhydrous sodium sulfate The solvent was then distilled off under reduced pressure the residue was purified by flash column chromatography (packing: silica gel 300 g; ether-hexane 5:1)

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 g (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 g (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 g (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 g (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 g (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 g (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 50 mL round bottom flask equipped with magnetic stir bar and condenser was charged with 6.0 g of 2-trimethylsilyloxy-1,3-cyclohexadiene, 3.5 g methyl tetrolate in 3 mL dry toluene. The reaction was heated to 150° C. for 50 hours at which point 1H-NMR indicated no starting diene. The raction was concentrated in vacuo to provide 5.7 g (67%) methyl 2-methyl-4-trimethylsilyloxybenzoate. A 50 mL round bottom flask equipped with magnetic stir bar and condenser The raction was concentrated in vacuo

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 25 mL of 2-(trimethylsilyloxy)-1,3-cyclohexadiene and 13 mL of α-acetoxyacrylonitrile were mixed and heated at 150° C. in a closed vessel for 22 h. The obtained dark orange viscous oil was dissolved in 200 mL of MeOH. After dropwise addition of a solution of 2.2 g of sodium methoxide in 150 mL of MeOH the reaction mixture was stirred for 3 h at rt, poured into ice/water and extracted with DCM. The organic phases were concentrated in vacuo and the crude residue was purified by CC with EtOAc-Hept (1:2) to yield 7.9 g of rac-(1R*,4R*)-bicyclo[2.2.2]octane-2,5-dione. extracted with DCM The organic phases were concentrated in vacuo the crude residue was purified by CC with EtOAc-Hept (1:2)

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 25 mL of 2-(trimethylsilyloxy)-1,3-cyclohexadiene and 13 mL of α-acetoxyacrylonitrile were mixed and heated at 150° C. in a closed vessel for 22 h. The obtained dark orange viscous oil was dissolved in 200 mL of MeOH. After dropwise addition of a solution of 2.2 g of sodium methoxide in 150 mL of MeOH the reaction mixture was stirred for 3 h at rt, poured into ice/water and extracted with DCM. The organic phases were concentrated in vacuo and the crude residue was purified by CC with EtOAc-Hept (1:2) to yield 7.9 g of rac-(1R*,4R*)-bicyclo[2.2.2]octane-2,5-dione. extracted with DCM The organic phases were concentrated in vacuo the crude residue was purified by CC with EtOAc-Hept (1:2)