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.;