Iridium Pincer-Catalyzed Dehydrogenation of Ethers Featuring Ethylene as the Hydrogen Acceptor

We describe efficient methods to dehydrogenate ethers by using iridium pincer complexes ((ipr4)Anthraphos)-Ir(H)(Cl), 4, (PC)-P-ipr4(sp(3))P-Ir(H)(Cl) 5, and ((PCP)-P-ipr4)-Ir(H)(Cl), 6. At 120 degrees C, cyclic ethers were dehydrogenated with high turnover numbers (over 400 in many cases). Acyclic ethers such as diethyl ether can also be dehydrogenated catalytically with TONs up to 90. The efficient dehydrogenation of cyclic and acyclic ethers using ethylene as a more practical hydrogen acceptor has been demonstrated for the first time.