99501-03-8Relevant articles and documents
A well-defined monomeric aluminum complex as an efficient and general catalyst in the Meerwein-Ponndorf-Verley reduction
McNerney, Brian,Whittlesey, Bruce,Cordes, David B.,Krempner, Clemens
, p. 14959 - 14964 (2014)
The metal-catalyzed Meerwein-Ponndorf-Verley (MPV) reduction allows for the mild and sustainable reduction of aldehydes and ketones but has not found widespread application in organic synthesis due to the high catalyst loading often required to obtain satisfactory yields of the reduced product. We report here on the synthesis and structure of a sterically extremely overloaded siloxide-supported aluminum isopropoxide capable of catalytically reducing a wide range of aldehydes and ketones (52 examples) in excellent yields under mild conditions and with low catalyst loadings. The unseen activity of the developed catalyst system in MPV reductions is due to its unique monomeric nature and the neutral donor isopropanol weakly coordinating to the aluminum center. The present work implies that monomeric aluminum alkoxide catalysts may be attractive alternatives to transition-metalbased systems for the selective reduction of aldehydes and ketones to primary and secondary alcohols.
Mild sp2Carbon-Oxygen Bond Activation by an Isolable Ruthenium(II) Bis(dinitrogen) Complex: Experiment and Theory
Lau, Samantha,Ward, Bryan,Zhou, Xueer,White, Andrew J.P.,Casely, Ian J.,MacGregor, Stuart A.,Crimmin, Mark R.
supporting information, p. 3654 - 3663 (2017/10/03)
The isolable ruthenium(II) bis(dinitrogen) complex [Ru(H)2(N2)2(PCy3)2] (1) reacts with aryl ethers (Ar-OR, R = Me and Ar) containing a ketone directing group to effect sp2C-O bond activation at temperatures below 40 °C. DFT studies support a low-energy Ru(II)/Ru(IV) pathway for C-O bond activation: oxidative addition of the C-O bond to Ru(II) occurs in an asynchronous manner with Ru-C bond formation preceding C-O bond breaking. Alternative pathways based on a Ru(0)/Ru(II) couple are competitive but less accessible due to the high energy of the Ru(0) precursors. Both experimentally and by DFT calculations, sp2C-H bond activation is shown to be more facile than sp2C-O bond activation. The kinetic preference for C-H bond activation over C-O activation is attributed to unfavorable approach of the C-O bond toward the metal in the selectivity determining step of the reaction pathway.
A mild and efficient flow procedure for the transfer hydrogenation of ketones and aldehydes using hydrous zirconia
Battilocchio, Claudio,Hawkins, Joel M.,Ley, Steven V.
supporting information, p. 2278 - 2281 (2013/06/05)
A flow chemistry Meerwein-Ponndorf-Verley (MPV) reduction procedure using partially hydrated zirconium oxide via a machine-assisted approach is reported. The heterogeneous reductive system could be applied to a wide range of functionalized substrates, allowing clean and fast delivery of the alcohol products within a few minutes (6-75 min). In three examples the system was scaled to deliver 50 mmol of product.