Cationic rhodium(I) complex-catalyzed σ- and π-bond activation cascade: Isomerization of allyl propargyl ethers to allenic aldehydes and dienals

Abstract

A cationic rhodium(I)/1,1'-bis(diphenylphosphino)ferrocene (dppf) complex catalyzes isomerization of allyl propargyl ethers to allenic aldehydes in good yields at room temperature 40 °C. At 80 °C, carbonyl migration from allenic aldehydes proceeds further to give dienals in good yields. The cationic rhodium(I)/dppf complex acts as a dual catalyst for activation of σ- and π-bonds in these isomerization reactions.