78638-64-9

Upstream product

• 66255-92-3 (R)-(+)-styrene-2,2-d2 oxide 
• 17537-31-4 Acetophenone-methyl-d3 
• 21210-43-5 (S)-Methyl mandelate 
• 17199-29-0 (S)-Mandelic acid 
• 108-22-5 Isopropenyl acetate 
• 17537-32-5 2,2,2-trideuterio-1-phenylethanol 
• 98-86-2 acetophenone 

Relevant academic research and scientific papers

Cationic NHC-Phosphine Iridium Complexes: Highly Active Catalysts for Base-Free Hydrogenation of Ketones

Novel bidentate N-heterocyclic carbene-phosphine iridium complexes have been synthesized and evaluated in the hydrogenation of ketones. Reported catalytic systems require base additives and, if excluded, need elevated temperature or high pressure of hydrogen gas to achieve satisfactory reactivity. The developed catalysts showed extremely high reactivity and good enantioselectivity under base-free and mild conditions. In the presence of 1 mol % catalyst under 1 bar hydrogen pressure at room temperature, hydrogenation was complete in 30 minutes giving up to 96 % ee. Again, this high reactivity was achieved in additive-free conditions. Mechanistic experiments demonstrated that balloon pressure of hydrogen was sufficient to form the activate species by reducing and eliminating the 1,5-cyclooctadiene ligand. The pre-activated catalyst was able to hydrogenate acetophenone with 89 % conversion in 5 min.

Mechanism of Homogeneously and Heterogeneously Catalysed Meerwein-Ponndorf-Verley-Oppenauer Reactions for the Racemisation of Secondary Alcohols

The mechanism of hydrogen transfer from alcohols to ketones, catalysed by lanthanide(III) isopropoxides or zeolite Beta has been studied. For the lanthanide catalysed reactions, (S)-1-phenyl-(1-2H 1)ethanol and acetophenone were used as case studies to determine the reaction pathway for the hydrogen transfer. Upon complete racemisation all deuterium was present at the 1-position, indicating that the reaction exclusively takes place via a carbon-to-carbon hydrogen transfer. Zeolite Beta with different Si/Al ratios was applied in the racemisation of (S)-1-phenylethanol. In this case the racemisation does not proceed via an oxidation/reduction pathway but via elimination of the hydroxy group and its readdition. This mechanism, however, is not characteristic for all racemisation reactions with zeolite Beta. When 4-tert-butyl cyclohexanone is reduced with this catalyst, a classical MPV reaction takes place exclusively. This demonstrates that zeolite Beta has a substrate dependent reaction pathway.

Stereospecific oxygen rearrangement in the reduction of optically pure methyl mandelate to phenylethanol isomers

The reduction of methyl (S)-(+)-mandelate, 1, produces the expected 2-phenylethanol, 3, and the unexpected optically pure 1-phenylethanol, 6, by a stereospecific oxygen atom metathesis; which occurs through a styrene oxide intermediate, whose concentration varies with solvent polarity.

Stereochemical Course of the "Mixed Hydride" (AlD3 and AlCl2H) Reduction of Optically Active Styrene-2,2-d2 Oxide

The reduction of (R)-(+)-styrene-2,2-d2 oxide with aluminum deuteride (AlD3) in diethyl ether at 0 deg C gives a nearly equal mixture of (S)-(+)-1-phenylethanol-2,2,2-d3 and (S)-(-)-2-phenylethanol-1,1,2-d3, the latter being formed with almost complete in