Rhenium Catalysts. VII. Rhenium(VI) Oxide¹

Organic Functional Group Hydrogenation

“…The hydrogenation of carboxylic acids and their derivatives is a very difficult reaction. It is accomplished, though, using ruthenium [63], rhenium oxide [64], o r copper-chromium oxide [65] at high temperatures and pressures. Acids, esters, and lactones a r e converted to alcohols, and amides, imides, and lactams give amines.…”

Catalytic Hydrogenation of Chiral α-Amino and α-Hydroxy Esters at Room Temperature with Nishimura Catalyst without Racemization

“…[8] He et al [9] modified supported Rh, Pt, Pd, and Ru catalysts or the corresponding metal salts with Mo, Re, or W carbonyls and the resulting bimetallic catalysts were able to reduce carboxylic acids at 145°C/100 bar. Other catalyst systems able to reduce carboxylic acids below 200°C were Re oxides (150 À 250°C, 150 À 300 bar), [10,11] homogeneous Ziegler-type Ni catalysts and Ru chloride complexes, [12] and Ru-CO-clusters bearing P(CH 2 OH) 3 ligands (100 À 130°C and 130 bar). [13] The application of these catalysts to the hydrogenation of chiral acids was not investigated but we suspect that racemization would occur above 100°C.…”

Mild Hydrogenation of Amides to Amines over a Platinum‐Vanadium Bimetallic Catalyst

“…[6] Thea chievement of hydrogenation of amides under mild reaction conditions, ideally lower than 30 bar H 2 and 70 8 8C, [6] is listed as aleading candidate in 12 key innovative research areas for the future sustainable production of pharmaceuticals. [11][12][13][14][15][16] Recently,o ther Re-based multi-metallic catalytic systems such as Pt/Re/In, [17] Pt/Re/ TiO 2 , [18] and Pd/Re/carbon [19] have enabled the use of lower H 2 pressures (5-70 bar) and temperatures (120-160 8 8C). In 1988, Dobson reported ac atalyst with much improved efficiency, namely abimetallic Pd/Re catalyst enabled amide hydrogenation at 130 bar H 2 and 200 8 8C.…”