1.1: LDA / tetrahydrofuran; hexane / 1.5 h / -70 - 10 °C 1.2: 33 percent / tetrahydrofuran; hexane / 20 °C 2.1: 86 percent / aq. TFA / 20 °C 3.1: H2O / 2 h / 90 °C 3.2: 91 percent / aq. HCl / 21 - 90 °C 4.1: disodium tetraborate decahydrate; aq. NaOH; D-hydantoinase / dimethylsulfoxide / 45 h / 45 °C / pH 10.5 5.1: 73.8 g / disodium tetraborate decahydrate; aq. HCl; D-carbamoylase / air / dimethylsulfoxide / 36 h / 45 °C / pH 8.02 View Scheme

1.1: LDA / tetrahydrofuran; hexane / 1.5 h / -70 - 10 °C 1.2: 33 percent / tetrahydrofuran; hexane / 20 °C 2.1: 86 percent / aq. TFA / 20 °C 3.1: H2O / 2 h / 90 °C 3.2: 91 percent / aq. HCl / 21 - 90 °C 4.1: disodium tetraborate decahydrate; aq. NaOH; D-hydantoinase / dimethylsulfoxide / 45 h / 45 °C / pH 10.5 5.1: 73.8 g / disodium tetraborate decahydrate; aq. HCl; D-carbamoylase / air / dimethylsulfoxide / 36 h / 45 °C / pH 8.02 6.1: 96 percent / Et3N; H2O / tetrahydrofuran / 16 h / 20 °C View Scheme

sodium hydride in tetrahydrofuran T=60°C; 1 h;