tri-isobutyl aluminium in n-heptane under N2 or Ar; vertical ball mill loaded with (AlH3)(n), i-Bu3Al, olefin (molar ratio 1:0.09:3.3) and heptane; stirred at 90-100°C for 3h; filtered; ppt. washed with heptane; solvent and excess olefin removed invac.; elem. anal.;