ethyl (E)-3-cyclobutylprop-2-enoate

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

Procedure: N-benzylhydroxylamine hydrochloride (0.77 g, 4.82 mmol) and triethylamine (0.76 mL, 5.45 mmol) were successively added to a solution of (E)-ethyl 3-cyclobutylacrylate, 46a, (0.65 g, 4.19 mmol) in dry dichloromethane (23.5 mL). The reaction mixture was allowed to stir at room temperature under an atmosphere of nitrogen for 3 days. The mixture was diluted with 75 mL of water and the layers were separated. The aqueous phase was reextracted twice more with dichloromethane (50 mL). The combined organic phases were dried over MgSO4, filtered and evaporated to dryness. The residue was purified via silica gel chromatography (0-100% EtOAc/Hexanes gradient) to afford 834 mg (86%) of the desired product: 1H NMR (400 MHz, CDCl3) δ 7.38-7.26 (m, 5H), 4.64 (s, 1H), 3.82 (q, J=13.5 Hz, 2H), 3.37-3.18 (m, 1H), 2.80-2.52 (m, 2H), 2.33 (dd, J=14.5, 5.1 Hz, 1H), 2.22-2.09 (m, 1H), 2.01-1.68 (m, 5H). the layers were separated The combined organic phases were dried over MgSO4 filtered evaporated to dryness The residue was purified via silica gel chromatography (0-100% EtOAc/Hexanes gradient)

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

Procedure: Ethyl 2-triphenylphosphoranylideneacetate (9.32 g, 26.74 mmol) was added to a solution of cyclobutanecarbaldehyde, 45a, (1.50 g, 17.83 mmol) in dichloromethane (30 mL). The reaction mixture was briefly purged with nitrogen and capped allowed to stir at room temperature overnight. All volatiles were removed at reduced pressure and the residue was dissolved in Et2O (100 mL) and hexanes (25 mL). The resulting pink precipitate was filtered off and discarded. The solvent was removed from the filtrate at reduced pressure. The crude product was purified via silica gel chromatography (0-20% EtOAc/Hexanes gradient) to afford 646 mg (23%) of the desired product: 1H NMR (400 MHz, CDCl3) δ 7.05 (dd, J=15.6, 6.8 Hz, 1H), 5.73 (dd, J=15.6, 1.4 Hz, 1H), 4.29-4.09 (m, 2H), 3.20-2.98 (m, 1H), 2.28-2.09 (m, 2H), 2.04-1.78 (m, 4H), 1.36-1.18 (m, 3H). The reaction mixture was briefly purged with nitrogen capped All volatiles were removed at reduced pressure the residue was dissolved in Et2O (100 mL) The resulting pink precipitate was filtered off The solvent was removed from the filtrate at reduced pressure The crude product was purified via silica gel chromatography (0-20% EtOAc/Hexanes gradient)

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

Procedure: N-benzylhydroxylamine hydrochloride (0.77 g, 4.82 mmol) and triethylamine (0.76 mL, 5.45 mmol) were successively added to a solution of (E)-ethyl 3-cyclobutylacrylate, 46a, (0.65 g, 4.19 mmol) in dry dichloromethane (23.5 mL). The reaction mixture was allowed to stir at room temperature under an atmosphere of nitrogen for 3 days. The mixture was diluted with 75 mL of water and the layers were separated. The aqueous phase was reextracted twice more with dichloromethane (50 mL). The combined organic phases were dried over MgSO4, filtered and evaporated to dryness. The residue was purified via silica gel chromatography (0-100% EtOAc/Hexanes gradient) to afford 834 mg (86%) of the desired product: 1H NMR (400 MHz, CDCl3) δ 7.38-7.26 (m, 5H), 4.64 (s, 1H), 3.82 (q, J=13.5 Hz, 2H), 3.37-3.18 (m, 1H), 2.80-2.52 (m, 2H), 2.33 (dd, J=14.5, 5.1 Hz, 1H), 2.22-2.09 (m, 1H), 2.01-1.68 (m, 5H). the layers were separated The combined organic phases were dried over MgSO4 filtered evaporated to dryness The residue was purified via silica gel chromatography (0-100% EtOAc/Hexanes gradient)

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

Procedure: Ethyl 2-triphenylphosphoranylideneacetate (9.32 g, 26.74 mmol) was added to a solution of cyclobutanecarbaldehyde, 45a, (1.50 g, 17.83 mmol) in dichloromethane (30 mL). The reaction mixture was briefly purged with nitrogen and capped allowed to stir at room temperature overnight. All volatiles were removed at reduced pressure and the residue was dissolved in Et2O (100 mL) and hexanes (25 mL). The resulting pink precipitate was filtered off and discarded. The solvent was removed from the filtrate at reduced pressure. The crude product was purified via silica gel chromatography (0-20% EtOAc/Hexanes gradient) to afford 646 mg (23%) of the desired product: 1H NMR (400 MHz, CDCl3) δ 7.05 (dd, J=15.6, 6.8 Hz, 1H), 5.73 (dd, J=15.6, 1.4 Hz, 1H), 4.29-4.09 (m, 2H), 3.20-2.98 (m, 1H), 2.28-2.09 (m, 2H), 2.04-1.78 (m, 4H), 1.36-1.18 (m, 3H). The reaction mixture was briefly purged with nitrogen capped All volatiles were removed at reduced pressure the residue was dissolved in Et2O (100 mL) The resulting pink precipitate was filtered off The solvent was removed from the filtrate at reduced pressure The crude product was purified via silica gel chromatography (0-20% EtOAc/Hexanes gradient)

Conditions: temp:45.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methyl (3S)-3-cyclobutyl-3-(3-hydroxyphenyl)propanoate or methyl (3R)-3-cyclobutyl-3-(3-hydroxyphenyl)propanoate (70). A mixture of 3-hydroxyphenylboronic acid (available from Aldrich) (2.2 g, 16 mmol) and hydroxy[(S)-BINAP]-rhodium(I) dimer (0.24 g, 0.16 mmol) in 1,4-dioxane (10 mL, 3.2 mmol) was sparged with N2. To the mixture were added water (1.0 mL, 3.2 mmol) and (E)-ethyl 3-cyclobutylacrylate 70.C (0.56 mL, 3.2 mmol). The resulting red-brown solution was warmed to 45° C. and stirred for 3 hours (sealed vial). The mixture was cooled to room temperature, diluted with EtOAc, washed with saturated aqueous NaHCO3 and brine, dried (MgSO4), and concentrated. The crude product was purified by silica gel flash chromatography (0-25% EtOAc/hexane) to afford (S)-ethyl 3-cyclobutyl-3-(3-hydroxyphenyl)propanoate or (R)-ethyl 3-cyclobutyl-3-(3-hydroxyphenyl)propanoate 70 as a pale yellow oil (0.77 g, 96%) (92% e.e.). The enantiomerically enriched mixture was further purified by chiral HPLC (Chiralcel OD, 3% i-PrOH/hexane, 220 nm) to afford 70 as a colorless oil (>99% e.e.). was sparged with N2 (sealed vial) The mixture was cooled to room temperature washed with saturated aqueous NaHCO3 and brine dried (MgSO4) concentrated The crude product was purified by silica gel flash chromatography (0-25% EtOAc/hexane)

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of lithium chloride (2.22 g, 52.2 mmol) in MeCN (80 mL) were added ethyl 2-(diethoxyphosphoryl)acetate (available from Aldrich) (8.37 mL, 41.8 mmol) and DBU (16.7 mL, 111 mmol) at room temperature. The mixture was cooled to 0° C., and to it was added cyclobutanecarbaldehyde 70.B (2.93 g, 34.8 mmol) dropwise. The resulting cloudy mixture was warmed to room temperature and stirred overnight. The mixture was partitioned between water and EtOAc. The layers were separated, and the aqueous phase was extracted with additional EtOAc. The combined organic layers were washed with water and brine, dried (MgSO4), and concentrated. The residue was purified by silica gel flash chromatography (0-10% EtOAc/hexane) to afford (E)-ethyl 3-cyclobutylacrylate 70.C as a colorless liquid (5.00 g, 94%). The resulting cloudy mixture was warmed to room temperature The mixture was partitioned between water and EtOAc The layers were separated the aqueous phase was extracted with additional EtOAc The combined organic layers were washed with water and brine dried (MgSO4) concentrated The residue was purified by silica gel flash chromatography (0-10% EtOAc/hexane)

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

Procedure: N-benzylhydroxylamine hydrochloride (0.77 g, 4.82 mmol) and triethylamine (0.76 mL, 5.45 mmol) were successively added to a solution of (E)-ethyl 3-cyclobutylacrylate, 46a, (0.65 g, 4.19 mmol) in dry dichloromethane (23.5 mL). The reaction mixture was allowed to stir at room temperature under an atmosphere of nitrogen for 3 days. The mixture was diluted with 75 mL of water and the layers were separated. The aqueous phase was reextracted twice more with dichloromethane (50 mL). The combined organic phases were dried over MgSO4, filtered and evaporated to dryness. The residue was purified via silica gel chromatography (0-100% EtOAc/Hexanes gradient) to afford 834 mg (86%) of the desired product: 1H NMR (400 MHz, CDCl3) δ 7.38-7.26 (m, 5H), 4.64 (s, 1H), 3.82 (q, J=13.5 Hz, 2H), 3.37-3.18 (m, 1H), 2.80-2.52 (m, 2H), 2.33 (dd, J=14.5, 5.1 Hz, 1H), 2.22-2.09 (m, 1H), 2.01-1.68 (m, 5H). the layers were separated The combined organic phases were dried over MgSO4 filtered evaporated to dryness The residue was purified via silica gel chromatography (0-100% EtOAc/Hexanes gradient)

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

Procedure: Ethyl 2-triphenylphosphoranylideneacetate (9.32 g, 26.74 mmol) was added to a solution of cyclobutanecarbaldehyde, 45a, (1.50 g, 17.83 mmol) in dichloromethane (30 mL). The reaction mixture was briefly purged with nitrogen and capped allowed to stir at room temperature overnight. All volatiles were removed at reduced pressure and the residue was dissolved in Et2O (100 mL) and hexanes (25 mL). The resulting pink precipitate was filtered off and discarded. The solvent was removed from the filtrate at reduced pressure. The crude product was purified via silica gel chromatography (0-20% EtOAc/Hexanes gradient) to afford 646 mg (23%) of the desired product: 1H NMR (400 MHz, CDCl3) δ 7.05 (dd, J=15.6, 6.8 Hz, 1H), 5.73 (dd, J=15.6, 1.4 Hz, 1H), 4.29-4.09 (m, 2H), 3.20-2.98 (m, 1H), 2.28-2.09 (m, 2H), 2.04-1.78 (m, 4H), 1.36-1.18 (m, 3H). The reaction mixture was briefly purged with nitrogen capped All volatiles were removed at reduced pressure the residue was dissolved in Et2O (100 mL) The resulting pink precipitate was filtered off The solvent was removed from the filtrate at reduced pressure The crude product was purified via silica gel chromatography (0-20% EtOAc/Hexanes gradient)