2-bromo-1-(oxolan-2-yl)ethanone

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: The crude thiol was dissolved in acetone (35ml) and treated with a solution of (RS)-2-bromoacetyltetrahydrofuran (3.48g, 18.0mmol) in acetone (5ml). After 10 min, potassium carbonate (1.24g, 8.9mmol) was added, and the mixture stirred for a further 30 min. The reaction mixture was diluted with ethyl acetate, washed successively with water (x2) and brine, dried and concentrated. The residue was flash chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40g, 55%); vmax (CH2Cl2) 3409, 1781, 1745, 1684, 1613, 1516cm-1. [Mass spectrum +ve ion (3-nitrobenzyl alcohol, sodium acetate) MNa+ (565)]. washed successively with water (x2) and brine dried concentrated chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40g, 55%)

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

Procedure: A stream of diazomethane (from N-methyl-N-nitrosotoluene-4-sulphonamide, 18.0g) in argon (P. Lombardi, Chem. and Ind., 1990, (21), 708) was passed into a solution of (RS)-tetrahydrofuroyl chloride [prepared from (RS)-tetrahydrofuroic acid (3.48g, 30mmol) as described in Example 2(a)] in dichloromethane (60ml) cooled in an ice bath. When the diazomethane addition was complete, 48% aqueous hydrogen bromide (5.6ml, 33.2mmol) was added. The mixture was stirred 0.25h then washed twice with water, dried, concentrated and flash chromaographed on silica gel eluting with 10% ethyl acetate in hexane to give the title compound as a pale yellow oil (4.44g, 77%); vmax (CH2Cl2) 1733, 1245, 1073 and 938cm-1 ; δH (CDCl3) 1.85-2.35 (4H, m), 3.85-4.05 (2H, m), 4.20 (2H, s), 4.54 (1H, dd, J 6.1, 8.2Hz). [Mass spectrum: +ve ion (ammonia) MNH4+ (210)]. cooled in an ice bath then washed twice with water dried concentrated

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

Procedure: The crude thiol was dissolved in acetone (35 ml) and treated with a solution of (RS)-2-bromoacetyltetrahydrofuran (3.48 g, 18.0 mmol) in acetone (5 ml). After 10 min, potassium carbonate (1.24 g, 8.9 mmol) was added, and the mixture stirred for a further 30min. The reaction mixture was diluted with ethyl acetate, washed successively with water (x2) and brine, dried and concentrated. The residue was flash chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40 g, 55%); νmax (CH2Cl2) 3409, 1781, 1745, 1684, 1613, 1516 cm-1. [Mass spectrum +ve ion (3-nitrobenzyl alcohol, sodium acetate) MNa+ (565)]. washed successively with water (x2) and brine dried concentrated chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40 g, 55%)

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

Procedure: A stream of diazomethane (from N-methyl-N-nitrosotoluene-4-sulphonamide, 18.0 g) in argon (P. Lombardi, Chem. and Ind., 1990, (21), 708) was passed into a solution of (RS)-tetrahydrofuroyl chloride [prepared from (RS)-tetrahydrofuroic acid (3.48 g, 30 mmol) as described in Example 2(a)] in dichloromethane (60 ml) cooled in an ice bath. When the diazomethane addition was complete, 48% aqueous hydrogen bromide (5.6 ml, 33.2 mmol) was added. The mixture was stirred 0.25 h then washed twice with water, dried, concentrated and flash chromaographed on silica gel eluting with 10% ethyl acetate in hexane to give the title compound as a pale yellow oil (4.44 g, 77%); νmax (CH2Cl2) 1733, 1245, 1073 and 938 cm-1 ; δH (CDCl3) 1.85-2.35 (4 H, m), 3.85-4.05 (2 H, m), 4.20 (2 H, s), 4.54 (1 H, dd, J 6.1, 8.2 Hz). [Mass spectrum: +ve ion (ammonia) MNH4+ (210)]. cooled in an ice bath then washed twice with water dried concentrated

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

Procedure: The crude thiol was dissolved in acetone (35ml) and treated with a solution of (RS)-2-bromoacetyltetrahydrofuran (3.48g, 18.0mmol) in acetone (5ml). After 10 min, potassium carbonate (1.24g, 8.9mmol) was added, and the mixture stirred for a further 30 min. The reaction mixture was diluted with ethyl acetate, washed successively with water (x2) and brine, dried and concentrated. The residue was flash chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40g, 55%); vmax (CH2Cl2) 3409, 1781, 1745, 1684, 1613, 1516cm-1. [Mass spectrum +ve ion (3-nitrobenzyl alcohol, sodium acetate) MNa+ (565)]. washed successively with water (x2) and brine dried concentrated chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40g, 55%)

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

Procedure: A stream of diazomethane (from N-methyl-N-nitrosotoluene-4-sulphonamide, 18.0g) in argon (P. Lombardi, Chem. and Ind., 1990, (21), 708) was passed into a solution of (RS)-tetrahydrofuroyl chloride [prepared from (RS)-tetrahydrofuroic acid (3.48g, 30mmol) as described in Example 2(a)] in dichloromethane (60ml) cooled in an ice bath. When the diazomethane addition was complete, 48% aqueous hydrogen bromide (5.6ml, 33.2mmol) was added. The mixture was stirred 0.25h then washed twice with water, dried, concentrated and flash chromaographed on silica gel eluting with 10% ethyl acetate in hexane to give the title compound as a pale yellow oil (4.44g, 77%); vmax (CH2Cl2) 1733, 1245, 1073 and 938cm-1 ; δH (CDCl3) 1.85-2.35 (4H, m), 3.85-4.05 (2H, m), 4.20 (2H, s), 4.54 (1H, dd, J 6.1, 8.2Hz). [Mass spectrum: +ve ion (ammonia) MNH4+ (210)]. cooled in an ice bath then washed twice with water dried concentrated

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: The crude thiol was dissolved in acetone (35 ml) and treated with a solution of (RS)-2-bromoacetyltetrahydrofuran (3.48 g, 18.0 mmol) in acetone (5 ml). After 10 min, potassium carbonate (1.24 g, 8.9 mmol) was added, and the mixture stirred for a further 30 min. The reaction mixture was diluted with ethyl acetate, washed successively with water (×2) and brine, dried and concentrated. The residue was flash chromatographed on silica gel eluting with 50, 70 and is 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40 g, 55%); νmax (CH2Cl2) 3409, 1781, 1745, 1684, 1613, 1516 cm-1. [Mass spectrum +ve ion (3-nitrobenzyl alcohol, sodium acetate) MNa+ (565)]. washed successively with water (×2) and brine dried concentrated chromatographed on silica gel eluting with 50, 70

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

Procedure: A stream of diazomethane (from N-methyl-N-nitrosotoluene-4-sulphonamide, 18.0 g) in argon (P. Lombardi, Chem. and Ind., 1990, (21), 708) was passed into a solution of (RS)-tetrahydrofuroyl chloride [prepared from (RS)-tetrahydrofuroic acid (3.48 g, 30 mmol) as described in Example 2(a)] in dichloromethane (60 ml) cooled in an ice bath. When the diazomethane addition was complete, 48% aqueous hydrogen bromide (5.6 ml, 33.2 mmol) was added. The mixture was stirred 0.25 h then washed twice with water, dried, concentrated and flash chromaographed on silica gel eluting with 10% ethyl acetate in hexane to give the title compound as a pale yellow oil (4.44 g, 77%); νmax (CH2Cl2) 1733, 1245, 1073 and 938 cm-1 ; δH (CDCl3) 1.85-2.35 (4H, m), 3.85-4.05 (2H, m), 4.20 (2H, s), 4.54 (1H, dd, J 6.1, 8.2 Hz). [Mass spectrum: +ve ion (ammonia) MNH4+ (210)]. cooled in an ice bath then washed twice with water dried concentrated

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a 20-liter glass vessel was added methylene chloride (10.0 liters) followed by acetyltetrahydrofuran (838.0 g, 7.34 moles). The solution was then cooled back to −10° C. and triethylamine was added (854.0 g, 8.44 moles). The vessel was purged with nitrogen and trimethylsilane triflate (1713.0 g, 7.71 moles) was added dropwise at a maximum temperature of −8° C. Addition was typically complete in 45 minutes. After 15 minutes stirring, a sample was removed for TLC and GC analysis, which showed that the reaction was completed. N-bromosuccinimide (1340 g. 7.53 moles) was added to the solution at a maximum temperature of −5° C. over a period of approximately 45 minutes in six portions. After a 30 minute stirring, the solution was sampled for GC and TLC analysis, which showed that the reaction was completed. The solution was then transferred to a 50-liter separating vessel, and 5% sodium bicarbonate (5 liters) was added with caution. The solution was stirred and separated. The upper aqueous phase was discarded, and the methylene chloride phase was washed with water, dried over sodium sulphate, filtered and stored in a freezer before use in the next step. was added dropwise at a maximum temperature of −8° C Addition a sample was removed for TLC and GC analysis, which After a 30 minute stirring the solution was sampled for GC and TLC analysis, which separating vessel 5% sodium bicarbonate (5 liters) was added with caution The solution was stirred separated the methylene chloride phase was washed with water dried over sodium sulphate filtered

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

Procedure: The crude thiol was dissolved in acetone (35 ml) and treated with a solution of (RS)-2-bromoacetyltetrahydrofuran (3.48 g, 18.0 mmol) in acetone (5 ml). After 10 min, potassium carbonate (1.24 g, 8.9 mmol) was added, and the mixture stirred for a further 30min. The reaction mixture was diluted with ethyl acetate, washed successively with water (x2) and brine, dried and concentrated. The residue was flash chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40 g, 55%); νmax (CH2Cl2) 3409, 1781, 1745, 1684, 1613, 1516 cm-1. [Mass spectrum +ve ion (3-nitrobenzyl alcohol, sodium acetate) MNa+ (565)]. washed successively with water (x2) and brine dried concentrated chromatographed on silica gel eluting with 50, 70 and 80% ethyl acetate in hexane yielding the title compound as a colourless foam (5.40 g, 55%)