Cationic rhodium(I) complex-catalyzed &sigma;- and &pi;‑bond activation cascade: Isomerization of allyl propargyl ethers to allenic aldehydes and dienals

Tanaka, Ken; Okazaki, Eri; Shibata, Yu

doi:10.1351/PAC-CON-09-09-05

Pure Appl. Chem., 2010, Vol. 82, No. 7, pp. 1453-1460

http://dx.doi.org/10.1351/PAC-CON-09-09-05

Published online 2010-05-04

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

Ken Tanaka*, Eri Okazaki and Yu Shibata

Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan

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.