gem-Disubstituted alkenes are directly and readily etherified with alcohols using Al(OTf)(3) and Zr(OTf)(4) as recyclable Lewis acid catalysts. In contrast, primary or secondary alkene analogues were inert under these conditions, enabling excellent chemoselectivity. Lanthanide triflates are inactive as catalysts for such reactions, as is phosphoric acid. But a combination of these two otherwise inactive entities led to an 'assisted acidity' scenario that saw significant unmatched catalyst activity. All catalysts of this study are recyclable a number of times without loss of activity. (C) 2011 Elsevier B.V. All rights reserved.