Water compatible gold(III)-catalysed synthesis of unsymmetrical ethers from alcohols

An efficient and broad-scoped method for the preparation of unsymmetrical ethers from alcohols catalysed by the simplest and least expensive gold catalyst, NaAuCl₄, is described for the first time. The procedure enables the etherification of benzylic and tertiary alcohols with moderate to good yields under mild conditions with low catalyst loading. Symmetrical ethers, the usual side products in the etherification of alcohols, were not detected in this case. The formation of the racemic ether from a chiral benzyl alcohol suggests the intermediacy of a carbocation, which has not previously been postulated for gold-catalysed reactions involving alcohols.