1: tri-n-butyl-tin hydride; propargyl alcohol With 2,2'-azo-bisisobutyronitrile T=100°C; 5 h; 2: diiodomethane With diethylzinc in dichloromethane T=-50°C; Simmons-Smith reaction; 3: Methyltriphenylphosphonium bromide; catechol monotriflate Further stages;