Homologation Reaction of Alcohols and Esters

Homologation is the one-carbon extension reaction of organic compounds such as alcohols and carboxylic esters, and is very important. Cobalt, rhodium, and ruthenium complexes are known to be efficient catalysts. Methanol and methyl ester can be converted to ethanol and ethyl ester, respectively, using Ru/F [28] and Ru/Co [29] catalysts (Eq. 11.9). 

Synergistic effects are observed in the Ru/Rh [30] and Ru/Co [29, 31] catalytic systems. Ethanol is efficiently formed from methyl formate with a Ru/HCl catalyst. CO and hydrogen are produced in situ at pressures sufficiently high to induce homologation of the methyl group [32]. 

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