2,2-dimethoxyethoxycyclohexane

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

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Cyclohexanol (11.00 g) was added slowly over 2 hours to a stirred suspension of sodium hydride (4.80 g, 50% w/w dispersion in oil) in dry DMPU (100 ml) at 50° C. under argon. The mixture was stirred for an additional 30 minutes, then cooled to 5° C. and treated with 2-bromo-1,1-dimethoxyethane (16.9 g). Stirring was continued for 18 hours at ambient temperature. The mixture was then poured into ice-water (250 ml). The aqueous mixture was extracted with ether (4×100 ml). The combined extracts were washed successively with water (3×100 ml) and saturated brine (100 ml), then dried (MgSO4) and evaporated. Flash chromatography of the residue, eluting successively with hexane, 5% v/v ethyl acetate hexane and 10% v/v ethyl acetate/hexane, gave 2-cyclohexyloxy-1,1-dimethoxyethane as an oil (A) (7.32 g). This was used without further purification. Stirring was continued for 18 hours at ambient temperature The aqueous mixture was extracted with ether (4×100 ml) The combined extracts were washed successively with water (3×100 ml) and saturated brine (100 ml) dried (MgSO4) evaporated Flash chromatography of the residue, eluting successively with hexane, 5% v/v ethyl acetate hexane and 10% v/v ethyl acetate/hexane

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

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Acidify a mixture of (2,2-dimethoxyethoxy)cyclohexane and water (30 mL) to a pH of 1.0 with sulfuric acid (9.0 M aqueous solution), and connect the mixture to a short-path distillation head. Reduce the pressure to 26.7 kPa and heat the mixture to 100° C. for 1 h. Cool the mixture to room temperature, then extract the aqueous layer with TBME (2×75 mL). Wash the combined organic layers with saturated aqueous NaHCO3 (75 mL) and saturated aqueous NaCl (75 mL). Dry the organic phase over MgSO4, filter, and concentrate the filtrate under reduced pressure to furnish the title compound (634 mg, 51% yield). 1H NMR (400 MHz, CDCl3): δ 9.73 (t, J=1.0 Hz, 1H), 4.06 (d, J=1.0 Hz, 2H), 3.31 (tt, J=9.2, 3.9 Hz, 1H), 1.95-1.89 (m, 2H), 1.79-1.68 (m, 2H), 1.57-1.50 (m, 1H), 1.39-1.20 (m, 5H). Cool the mixture to room temperature extract the aqueous layer with TBME (2×75 mL) Wash the combined organic layers with saturated aqueous NaHCO3 (75 mL) and saturated aqueous NaCl (75 mL) Dry the organic phase over MgSO4 filter concentrate the filtrate under reduced pressure

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

Procedure: Dissolve cyclohexanol (2.00 mL, 19.1 mmol) in DMF (9.6 mL), then add NaHMDS (1 M solution in THF, 21.0 mL, 21.0 mmol), and stir the solution at room temperature for 5 min. Add 2-bromo-1,1-dimethoxyethane (2.26 mL, 19.1 mmol), then stir the mixture at room temperature under a nitrogen atmosphere for three days. Dilute the mixture with EtOAc (250 mL) and wash with saturated aqueous NaCl (2×250 mL). Dry the organic phase over MgSO4, filter, and concentrate the filtrate under reduced pressure. Subject the resulting crude material to silica gel chromatography eluting with a gradient of 0% to 10% EtOAc/hexanes. Concentrate the fractions containing the desired product under reduced pressure to furnish the title compound as a pale yellow oil (1.10 g, 31% yield). 1H NMR (400 MHz, CDCl3): δ 4.47 (t, J=5.3 Hz, 1H), 3.49 (d, J=5.3 Hz, 2H), 3.39 (s, 6H), 3.25 (tt, J=9.2, 3.7 Hz, 1H), 1.94-1.87 (m, 2H), 1.76-1.69 (m, 2H), 1.55-1.49 (m, 1H), 1.34-1.17 (m, 5H). wash with saturated aqueous NaCl (2×250 mL) Dry the organic phase over MgSO4 filter concentrate the filtrate under reduced pressure eluting with a gradient of 0% to 10% EtOAc/hexanes Concentrate the fractions containing the desired product under reduced pressure

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Cyclohexanol (11.00 g) was added slowly over 2 hours to a stirred suspension of sodium hydride (4.80 g, 50% w/w dispersion in oil) in dry DMPU (100 ml) at 50° C. under argon. The mixture was stirred for an additional 30 minutes, then cooled to 5° C. and treated with 2-bromo-1,1-dimethoxyethane (16.9 g). Stirring was continued for 18 hours at ambient temperature. The mixture was then poured into ice-water (250 ml). The aqueous mixture was extracted with ether (4×100 ml). The combined extracts were washed successively with water (3×100 ml) and saturated brine (100 ml), then dried (MgSO4) and evaporated. Flash chromatography of the residue, eluting successively with hexane, 5% v/v ethyl acetate hexane and 10% v/v ethyl acetate/hexane, gave 2-cyclohexyloxy-1,1-dimethoxyethane as an oil (A) (7.32 g). This was used without further purification. [A sample was distilled under vacuum (bulb to bulb transfer); NMR: 1.29 (5H,m), 1.55 (1H,m), 1.76 (2H,m), 1.92 (2H,m), 3.27 (1H,m), 3.40 (6H,s), 3.50 (2H,d J=5 Hz), 4.48 (1H,t J=5 Hz).] Stirring was continued for 18 hours at ambient temperature The aqueous mixture was extracted with ether (4×100 ml) The combined extracts were washed successively with water (3×100 ml) and saturated brine (100 ml) dried (MgSO4) evaporated Flash chromatography of the residue, eluting successively with hexane, 5% v/v ethyl acetate hexane and 10% v/v ethyl acetate/hexane

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Acidify a mixture of (2,2-dimethoxyethoxy)cyclohexane and water (30 mL) to a pH of 1.0 with sulfuric acid (9.0 M aqueous solution), and connect the mixture to a short-path distillation head. Reduce the pressure to 26.7 kPa and heat the mixture to 100° C. for 1 h. Cool the mixture to room temperature, then extract the aqueous layer with TBME (2×75 mL). Wash the combined organic layers with saturated aqueous NaHCO3 (75 mL) and saturated aqueous NaCl (75 mL). Dry the organic phase over MgSO4, filter, and concentrate the filtrate under reduced pressure to furnish the title compound (634 mg, 51% yield). 1H NMR (400 MHz, CDCl3): δ 9.73 (t, J=1.0 Hz, 1H), 4.06 (d, J=1.0 Hz, 2H), 3.31 (tt, J=9.2, 3.9 Hz, 1H), 1.95-1.89 (m, 2H), 1.79-1.68 (m, 2H), 1.57-1.50 (m, 1H), 1.39-1.20 (m, 5H). Cool the mixture to room temperature extract the aqueous layer with TBME (2×75 mL) Wash the combined organic layers with saturated aqueous NaHCO3 (75 mL) and saturated aqueous NaCl (75 mL) Dry the organic phase over MgSO4 filter concentrate the filtrate under reduced pressure

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

Procedure: Dissolve cyclohexanol (2.00 mL, 19.1 mmol) in DMF (9.6 mL), then add NaHMDS (1 M solution in THF, 21.0 mL, 21.0 mmol), and stir the solution at room temperature for 5 min. Add 2-bromo-1,1-dimethoxyethane (2.26 mL, 19.1 mmol), then stir the mixture at room temperature under a nitrogen atmosphere for three days. Dilute the mixture with EtOAc (250 mL) and wash with saturated aqueous NaCl (2×250 mL). Dry the organic phase over MgSO4, filter, and concentrate the filtrate under reduced pressure. Subject the resulting crude material to silica gel chromatography eluting with a gradient of 0% to 10% EtOAc/hexanes. Concentrate the fractions containing the desired product under reduced pressure to furnish the title compound as a pale yellow oil (1.10 g, 31% yield). 1H NMR (400 MHz, CDCl3): δ 4.47 (t, J=5.3 Hz, 1H), 3.49 (d, J=5.3 Hz, 2H), 3.39 (s, 6H), 3.25 (tt, J=9.2, 3.7 Hz, 1H), 1.94-1.87 (m, 2H), 1.76-1.69 (m, 2H), 1.55-1.49 (m, 1H), 1.34-1.17 (m, 5H). wash with saturated aqueous NaCl (2×250 mL) Dry the organic phase over MgSO4 filter concentrate the filtrate under reduced pressure eluting with a gradient of 0% to 10% EtOAc/hexanes Concentrate the fractions containing the desired product under reduced pressure

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Cyclohexanol (11.00 g) was added slowly over 2 hours to a stirred suspension of sodium hydride (4.80 g, 50% w/w dispersion in oil) in dry DMPU (100 ml) at 50° C. under argon. The mixture was stirred for an additional 30 minutes, then cooled to 5° C. and treated with 2-bromo-1,1-dimethoxyethane (16.9 g). Stirring was continued for 18 hours at ambient temperature. The mixture was then poured into ice-water (250 ml). The aqueous mixture was extracted with ether (4×100 ml). The combined extracts were washed successively with water (3×100 ml) and saturated brine (100 ml), then dried (MgSO4) and evaporated. Flash chromatography of the residue, eluting successively with hexane, 5% v/v ethyl acetate hexane and 10% v/v ethyl acetate/hexane, gave 2-cyclohexyloxy-1,1-dimethoxyethane as an oil (A) (7.32 g). This was used without further purification. Stirring was continued for 18 hours at ambient temperature The aqueous mixture was extracted with ether (4×100 ml) The combined extracts were washed successively with water (3×100 ml) and saturated brine (100 ml) dried (MgSO4) evaporated Flash chromatography of the residue, eluting successively with hexane, 5% v/v ethyl acetate hexane and 10% v/v ethyl acetate/hexane