Bimetallic-Catalyzed Reduction of Carboxylic Acids and Lactones to Alcohols and Diols

✍ Scribed by Arno Behr; Volker A. Brehme

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 127 KB
• Volume: 344
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/1615-4169(200207)344:5<525::aid-adsc525>3.0.co;2-u

✦ Synopsis

The homogeneously catalyzed reduction of carboxylic acids with hydrogen was studied. Bimetallic catalysts consisting of a group 8 or 9 late transition-metal and a second group 6 or 7 transition-metal carbonyl showed a synergistic effect allowing the conversion in good yields under moderate conditions. Besides the effect of different catalyst precursors, the influence of temperature, hydrogen pressure, and catalyst concentration was investigated. An equimolar mixture of [Rh(acac)(CO) 2 ] and [Mo(CO) 6 ] showed the highest activity and was therefore applied to the reduction of lactones to diols. The reduction potential of the catalyst was found to be dependent on the ring size of the lactone used. Five-membered ring lactones were hardly converted to diols whereas six-and seven-membered ring lactones reacted easily.