boron trifluoride diethyl etherate in dichloromethane Mixt. was stirred for 1 h at -78°C (inert atm.);; mixt. was quenched with satd. aq. NaHCO3 and warmed to room temp.; aq. phase was extd. with ether, organic phases were washed with brine, dried over anhyd. MgSO4, chromd. (hexane); elem. anal.;;

sodium hydrogencarbonate; tris(pentafluorophenyl)-borane in toluene under N2 or Ar; borane in toluene added to stirred soln. of stannane (molar ratio (5:1) in toluene at -78°C; stirred at -78°C for 5 h; quenched with satd. aq. NaHCO3; warmed to room temp.; layers sepd.; aq. layer extd. with Et2O; combined extracts dried (Na2SO4); filtered; concd.; purified by column chromy. (silica gel, EtOAc-hexane);

in deuterated toluene under N2 or Ar; in NMR tube; stannane in toluene-d8 added to borane (molar ratio 2:1) in toluene-d8 at -60°C; not isolated; monitored by (1)H and (119)Sn NMR spectra;