Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters.
Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity.
['Li|Yuehui|Y|', 'Topf|Christoph|C|', 'Cui|Xinjiang|X|', 'Junge|Kathrin|K|', 'Beller|Matthias|M|']
D002264:Carboxylic Acids D002384:Catalysis D056831:Coordination Complexes D004952:Esters D004987:Ethers D006865:Hydrogenation D058116:Lewis Acids D008698:Mesylates D010720:Phosphines D012428:Ruthenium
Lewis acids hydrogenation ethers homogeneous catalysis ruthenium