35 min) followed by the addition of 4/3 equiv of BF,-OEt,(0" C, 15 min) 3 provided the corresponding propargylic organoborane 3. To the reaction mixture were then added aldehydes or ketones (room temperature, 1.5 h), which on oxidative workup gave the corresponding trimethylsilylsubstituted a-allenic alcohols 5 in excellent isolated yields (Table I). None of the corresponding@-acetylenic alcohols were dete~ ted.~ The reactions ...