(7aS)-3,3,6,6-tetramethyl-7,7a-dihydro-1H-pyrrolo[1,2-c][1,3]oxazol-5-one

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes

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

Procedure: To a solution of (S)-3,3,6,6-tetramethyl-dihydropyrrolo[1,2-c]oxazol-5(1H,3H,6H)-one in methanol (20 mL) was added HCl (4 N in 1,4-dioxane, 10 mL, 40 mmol). The reaction mixture was stirred at RT for 30 min, concentrated to dryness, and re-dissolved in DCM (50 mL). To the resulting solution were added imidazole (1.5 g, 22 mmol) and TBS-Cl (2.8 g, 18.6 mmol) respectively. The mixture was stirred at RT overnight and filtered. The filtrate was concentrated and the residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-5-((tert-butyldimethylsilyloxy)methyl)-3,3-dimethylpyrrolidin-2-one (3.1 g, 71.2%). LRMS (M+H+) m/z 258.3. concentrated to dryness re-dissolved in DCM (50 mL) The mixture was stirred at RT overnight filtered The filtrate was concentrated the residue was purified on silica gel column a mixture of EtOAc and hexanes