1: [2-(1,3-dioxolan-2-yl)phenyl]phosphine With potassium tert-butylate in tetrahydrofuran T=-30 - 0°C; 1 h; 2: (4S,7S)-4,7-dimethyl-1,3,2-dioxathiepane 2,2-dioxide in tetrahydrofuran T=20°C; 2 h; 3: With potassium tert-butylate in tetrahydrofuran T=20°C; 48 h; Further stages.;