1: chloro-diphenylphosphine With lithium in tetrahydrofuran T=20°C; 3 h; 2: (1RS,2RS,3SR,4SR)-1,2,3,4-tetrakis(((tolyl-4-sylfonyl)oxy)methyl)cyclopentane in tetrahydrofuran T=20°C; 5 h; Further stages.;

1.1: 65 percent / pyridine / 5 h / -20 °C 2.1: Li / tetrahydrofuran / 3 h / 20 °C 2.2: tetrahydrofuran / 5 h / 20 °C View Scheme

1.1: 98 percent / water; Amberlite IR-120(H) / tetrahydrofuran / 2 h / 65 °C 2.1: 65 percent / pyridine / 5 h / -20 °C 3.1: Li / tetrahydrofuran / 3 h / 20 °C 3.2: tetrahydrofuran / 5 h / 20 °C View Scheme