1: trans-crotonic acid With potassium carbonate in N,N-dimethyl-formamide 0.5 h; Inert atmosphereCooling; 2: p-methoxybenzyl chloride in N,N-dimethyl-formamide T=20 - 45°C; 18 h; Inert atmosphereCooling with ice;

1: (4-methoxyphenyl)methanol With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: (S)-1-benzyl-2-[(E)-2-butenoyl]-5-isopropyl-pyrazolidin-3-one in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere; 3: With water; ammonium chloride in tetrahydrofuran; hexane T=20°C; Inert atmosphere; optical yield given as percent ee;

1: (4-methoxyphenyl)methanol With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: (S)-1-(1-naphthylmethyl)-2-[(E)-2-butenoyl]-5-isopropylpyrazolidin-3-one in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere; 3: With water; ammonium chloride in tetrahydrofuran; hexane T=20°C; Inert atmosphere; optical yield given as percent ee;

1: (4-methoxyphenyl)methanol With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: (S)-1-benzyl-2-[(E)-2-butenoyl]-5-tert-butyl-pyrazolidin-3-one in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere; 3: With water; ammonium chloride in tetrahydrofuran; hexane T=20°C; Inert atmosphere; optical yield given as percent ee;

basic alumina in ethyl acetate; Petroleum ether Alkaline conditions;

1: (4-methoxyphenyl)methanol With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: (S)-1-benzyl-2-[(E)-2-butenoyl]-5-phenyl-pyrazolidin-3-one in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere; 3: With water; ammonium chloride in tetrahydrofuran; hexane T=20°C; Inert atmosphere; optical yield given as percent ee;

1: (4-methoxyphenyl)methanol With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: 1-ethyl-2-[(E)-2-butenoyl]-5-isopropyl-pyrazolidin-3-one in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere; 3: With water; ammonium chloride in tetrahydrofuran; hexane T=20°C; Inert atmosphere; optical yield given as percent ee;

1: thionyl chloride / dichloromethane / 0 - 20 °C 2: tetrabutylammomium bromide; palladium(II) 2,4-pentanedionate / tetrahydrofuran / 24 h / 70 °C / 15001.5 Torr / |Autoclave 3: basic alumina / Petroleum ether; ethyl acetate / |Alkaline conditions View Scheme

1: tetrabutylammomium bromide; palladium(II) 2,4-pentanedionate / tetrahydrofuran / 24 h / 70 °C / 15001.5 Torr / |Autoclave 2: basic alumina / Petroleum ether; ethyl acetate / |Alkaline conditions View Scheme

1: sodium tetrahydroborate / tetrahydrofuran / 0 - 20 °C 2: thionyl chloride / dichloromethane / 0 - 20 °C 3: tetrabutylammomium bromide; palladium(II) 2,4-pentanedionate / tetrahydrofuran / 24 h / 70 °C / 15001.5 Torr / |Autoclave 4: basic alumina / Petroleum ether; ethyl acetate / |Alkaline conditions View Scheme