Enantioselective Vinylogous\nAddition of Enones to\nAllenes Enabled by Synergistic Borane/Palladium Catalysis

Herein,\nwe report a method for enantioselective\nvinylogous\naddition\nof enones to alkoxyallenes enabled by synergistic borane/palladium\ncatalysis. The inductive effect provided by borane coordination to\nthe ketone was essential for closing the gap between the conditions\nneeded for the generation of a dienolate and those needed for initiation\nof the palladium catalytic cycle by protonation of the metal catalyst.\nFurthermore, we accomplished the first example of stereodivergent\nsynthesis with chiral borane/transition-metal catalysts.