Cationic Rhodium(I)-dppf Complex-Catalyzed Olefin Isomerization/Propargyl Claisen Rearrangement/Carbonyl Migration Cascade

We have established that a cationic rhodium(I)-dppf complex catalyzes isomerizations of allyl propargyl ethers to allenic aldehydes in good yields from room temperature to 40 degrees C. On the other hand, carbonyl migration reactions from allenic aldehydes further proceed to give dienals in good yields at 80 degrees C.