in tetrachloromethane soln. of Br2 (1 mol) in CCl4 added dropwise at -10°C to soln. of (Z)-1-(2-(tribenzylstannyl)vinyl)-1-cycloheptanol (1 mol) in CCl4 with stirring; after addn. of Br2 react. mixt. was kept 4 h at room temp.; solvent evapd.; crystn. from cyclohexane; elem. anal.;