ethyl 8-oxa-1-azaspiro[4.5]decane-2-carboxylate

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

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

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

Procedure: To a solution of ethyl 8-oxa-1-azaspiro[4.5]decane-2-carboxylate (166) (135 mg, 0.63 mmol) in anhydrous dichloromethane (2 mL) was added Hunig's base (0.22 mL, 1.3 mmol) followed by acetyl chloride (0.05 mL, 0.76 mmol) and the reaction stirred at room temperature under nitrogen for 1.5 h. The reaction was diluted with dichloromethane and washed with 0.1 N HCl and the organic layer dried over MgSO4 and concentrated in vacuo. The residue was purified by silica gel chromatography eluting with 60-100% hexanes/EtOAc to afford the title compound as a yellow oil (94 mg, 58% yield). washed with 0.1 N HCl the organic layer dried over MgSO4 concentrated in vacuo The residue was purified by silica gel chromatography eluting with 60-100% hexanes/EtOAc

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

Procedure: To a solution of ethyl 8-oxa-1-azaspiro[4.5]decane-2-carboxylate (166) (125 mg, 0.59 mmol) in anhydrous dichloromethane (2 mL) was added silver cyanide (98 mg, 0.73 mmol) followed by N-[(methyloxy)carbonyl]-L-valyl chloride (142 mg, 0.73 mmol) as a solution in anhydrous dichloromethane (3.5 mL) and the solution stirred at room temperature for 18 h under nitrogen. The reaction is filtered and treated with methanol and stirred for 5 minutes. The reaction is concentrated in vacuo and the residue purified by silica gel chromatography eluting with 30-100% hexanes/EtOAc to afford the title compound as a white solid (43 mg, 20% yield). The reaction is filtered treated with methanol stirred for 5 minutes The reaction is concentrated in vacuo the residue purified by silica gel chromatography eluting with 30-100% hexanes/EtOAc

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

Procedure: To a solution of ethyl 1-[(4-nitrophenyl)sulfonyl]-8-oxa-1-azaspiro[4.5]decane-2-carboxylate (165) (1.47 g, 3.7 mmol) in anhydrous acetonitrile (25 mL) was added potassium carbonate (0.76 g, 5.5 mmol), 18-crown-6 (0.2 g, 0.7 mmol) and thiophenol (0.6 mL. 5.5 mmol) and the reaction stirred at room temperature for 18 h. The reaction was concentrated in vacuo and the residue dissolved in 0.1 N HCl. The aqueous layer was extracted twice with EtOAc and the organic layer was discarded. The aqueous layer was treated with solid potassium carbonate until the solution gave blue pH paper. It was extracted with 15% isopropanol/dichloromethane (3×) and the organic layer dried over sodium sulfate and concentrated in vacuo to afford the title compound as a clear oil (0.71 g, 90% yield). The reaction was concentrated in vacuo the residue dissolved in 0.1 N HCl The aqueous layer was extracted twice with EtOAc The aqueous layer was treated with solid potassium carbonate until the solution gave blue pH paper It was extracted with 15% isopropanol/dichloromethane (3×) the organic layer dried over sodium sulfate concentrated in vacuo

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

Procedure: To a solution of ethyl 8-oxa-1-azaspiro[4.5]decane-2-carboxylate (166) (135 mg, 0.63 mmol) in anhydrous dichloromethane (2 mL) was added Hunig's base (0.22 mL, 1.3 mmol) followed by acetyl chloride (0.05 mL, 0.76 mmol) and the reaction stirred at room temperature under nitrogen for 1.5 h. The reaction was diluted with dichloromethane and washed with 0.1 N HCl and the organic layer dried over MgSO4 and concentrated in vacuo. The residue was purified by silica gel chromatography eluting with 60-100% hexanes/EtOAc to afford the title compound as a yellow oil (94 mg, 58% yield). washed with 0.1 N HCl the organic layer dried over MgSO4 concentrated in vacuo The residue was purified by silica gel chromatography eluting with 60-100% hexanes/EtOAc

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

Procedure: To a solution of ethyl 8-oxa-1-azaspiro[4.5]decane-2-carboxylate (166) (125 mg, 0.59 mmol) in anhydrous dichloromethane (2 mL) was added silver cyanide (98 mg, 0.73 mmol) followed by N-[(methyloxy)carbonyl]-L-valyl chloride (142 mg, 0.73 mmol) as a solution in anhydrous dichloromethane (3.5 mL) and the solution stirred at room temperature for 18 h under nitrogen. The reaction is filtered and treated with methanol and stirred for 5 minutes. The reaction is concentrated in vacuo and the residue purified by silica gel chromatography eluting with 30-100% hexanes/EtOAc to afford the title compound as a white solid (43 mg, 20% yield). The reaction is filtered treated with methanol stirred for 5 minutes The reaction is concentrated in vacuo the residue purified by silica gel chromatography eluting with 30-100% hexanes/EtOAc

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

Procedure: To a solution of ethyl 8-oxa-1-azaspiro[4.5]decane-2-carboxylate (166) (125 mg, 0.59 mmol) in anhydrous dichloromethane (2 mL) was added silver cyanide (98 mg, 0.73 mmol) followed by N-[(methyloxy)carbonyl]-L-valyl chloride (142 mg, 0.73 mmol) as a solution in anhydrous dichloromethane (3.5 mL) and the solution stirred at room temperature for 18 h under nitrogen. The reaction is filtered and treated with methanol and stirred for 5 minutes. The reaction is concentrated in vacuo and the residue purified by silica gel chromatography eluting with 30-100% hexanes/EtOAc to afford the title compound as a white solid (43 mg, 20% yield). The reaction is filtered treated with methanol stirred for 5 minutes The reaction is concentrated in vacuo the residue purified by silica gel chromatography eluting with 30-100% hexanes/EtOAc

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

Procedure: To a solution of ethyl 1-[(4-nitrophenyl)sulfonyl]-8-oxa-1-azaspiro[4.5]decane-2-carboxylate (165) (1.47 g, 3.7 mmol) in anhydrous acetonitrile (25 mL) was added potassium carbonate (0.76 g, 5.5 mmol), 18-crown-6 (0.2 g, 0.7 mmol) and thiophenol (0.6 mL. 5.5 mmol) and the reaction stirred at room temperature for 18 h. The reaction was concentrated in vacuo and the residue dissolved in 0.1 N HCl. The aqueous layer was extracted twice with EtOAc and the organic layer was discarded. The aqueous layer was treated with solid potassium carbonate until the solution gave blue pH paper. It was extracted with 15% isopropanol/dichloromethane (3×) and the organic layer dried over sodium sulfate and concentrated in vacuo to afford the title compound as a clear oil (0.71 g, 90% yield). The reaction was concentrated in vacuo the residue dissolved in 0.1 N HCl The aqueous layer was extracted twice with EtOAc The aqueous layer was treated with solid potassium carbonate until the solution gave blue pH paper It was extracted with 15% isopropanol/dichloromethane (3×) the organic layer dried over sodium sulfate concentrated in vacuo

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

Procedure: To a solution of ethyl 1-[(4-nitrophenyl)sulfonyl]-8-oxa-1-azaspiro[4.5]decane-2-carboxylate (165) (1.47 g, 3.7 mmol) in anhydrous acetonitrile (25 mL) was added potassium carbonate (0.76 g, 5.5 mmol), 18-crown-6 (0.2 g, 0.7 mmol) and thiophenol (0.6 mL. 5.5 mmol) and the reaction stirred at room temperature for 18 h. The reaction was concentrated in vacuo and the residue dissolved in 0.1 N HCl. The aqueous layer was extracted twice with EtOAc and the organic layer was discarded. The aqueous layer was treated with solid potassium carbonate until the solution gave blue pH paper. It was extracted with 15% isopropanol/dichloromethane (3×) and the organic layer dried over sodium sulfate and concentrated in vacuo to afford the title compound as a clear oil (0.71 g, 90% yield). The reaction was concentrated in vacuo the residue dissolved in 0.1 N HCl The aqueous layer was extracted twice with EtOAc The aqueous layer was treated with solid potassium carbonate until the solution gave blue pH paper It was extracted with 15% isopropanol/dichloromethane (3×) the organic layer dried over sodium sulfate concentrated in vacuo

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

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