104292-58-2Relevant academic research and scientific papers
Selective hydrosilylation of alkynes and ketones: Contrasting reactivity between cationic 3-iminophosphine palladium and nickel complexes
Tafazolian, Hosein,Yoxtheimer, Robert,Thakuri, Rajendr S.,Schmidt, Joseph A. R.
supporting information, p. 5431 - 5440 (2017/04/28)
The catalytic hydrosilylation of alkynes and ketones has been explored utilizing palladium- and nickel(allyl) complexes supported by 3-iminophosphine ligands. Palladium and nickel demonstrated distinctly different reactivity profiles, with palladium provi
Highly Chemoselective Palladium-Catalyzed Conjugate Reduction of α,β-Unsaturated Carbonyl Compounds with Silicon Hydrides and Zinc Chloride Cocatalyst
Keinan, Ehud,Greenspoon, Noam
, p. 7314 - 7325 (2007/10/02)
A three-component system comparised of a soluble palladium catalyst, hydridosilane, and zinc chloride is capable of efficient conjugate reduction of α,β-unsaturated ketones and aldehydes.The optimal set of condition includes diphenylsilane as the most effective hydride donor, any soluble palladium complex in either the 0 or II oxidation state, when it is stabilized by phosphine ligands, and ZnCl2 as the best Lewis acid cocatalyst.The reaction is very general with respect to a broad range of unsaturated ketones and aldehydes, and it is highly selective for these Michael acceptors, as reduction of α,β-unsaturated carboxylic acid derivatives is very sluggish under these conditions.When dideuteriodiphenylsilane is used to reduce unsaturated ketones, deuterium is stereoselectively introduced at the less-hindered face of the substrate and regioselectively at the β-position.Conversely, when reductions are carried out in the presence of traces of D2O, deuterium incorporation occurs at the α-position.On the basis of deuterium-incorporation experiments and 1H NMR studies, a catalytic cycle is postulated in which the first step involves reversible coordination of the palladium complex to the electron-deficient olefin and oxidative addition of silicon hydride to form a hydropalladium olefin complex.Migratory insertion of hydride into the coordinated olefin produces an intermediate palladium enolate which, via reductive elimination, collapses back to the Pd(0) complex and a silyl enol ether, which is then hydrolyzed to the saturated ketone.In addition to catalyzing that hydrolysis, ZnCl2 facilitates the hydrosilation process.
