Reduction of Activated Alkenes by PIII/PV Redox Cycling Catalysis
The carbon–carbon double bond of unsaturated carbonyl compounds was readily reduced by using a phosphetane oxide catalyst in the presence of a simple organosilane as the terminal reductant and water as the hydrogen source. Quantitative hydrogenation was observed when 1.0 mol % of a methyl-substituted phosphetane oxide was employed as the catalyst. The procedure is highly selective towards activated double bonds, tolerating a variety of functional groups that are usually prone to reduction. In total, 25 alkenes and two alkynes were hydrogenated to the corresponding alkanes in excellent yields of up to 99 %. Notably, less active poly(methylhydrosiloxane) could also be utilized as the terminal reductant. Mechanistic investigations revealed the phosphane as the catalyst resting state and a protonation/deprotonation sequence as the crucial step in the catalytic cycle.
Longwitz, Lars,Werner, Thomas
supporting information
p. 2760 - 2763
(2020/02/05)
(BDP)CuH: A "hot" Stryker's reagent for use in achiral conjugate reductions
(Chemical Equation Presented) A ligand-modified, economical version of Stryker's reagent (SR) has been developed based on a bidentate, achiral bis-phosphine. Generated in situ, "(BDP)CuH" smoothly effects conjugate reductions of a variety of unsaturated substrates, including those that are normally unreactive toward SR. Substrate-to-ligand ratios typically on the order of 1000-10000:1 can be used leading to products in high yields.
Baker, Benjamin A.,Boskovic, Zarko V.,Lipshutz, Bruce H.
p. 289 - 292
(2008/09/19)
SYNTHESIS OF γ-KETOPIMELIC ACID DERIVATIVES BY RHODIUM CARBONYL-CATALYZED HYDROCARBONYLATION OF ACRYLIC ACID DERIVATIVES
The rhodium carbonyl-catalyzed reactions of acrylic acid derivatives (1) with CO in iso-propanol gave selectively γ-ketopimelic acid derivatives (2) in good yields.In the reaction of ethyl acrylate (1b) in iso-propanol-d8, deuterium scrambling in the methylene groups of the products (2b) was observed.
Hong, Pangbu,Mise, Takaya,Yamazaki, Hiroshi
p. 361 - 364
(2007/10/02)
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