Conversion of lactones into ethers

Although tetrahydrofurans and tetrahydropyrans are important structural subunits of many classes of natural products,l comparatively few general synthetic methods are known? Since y- and &lactones are readily available: an efficient and versatile transformation to the ether would significantly extend current methodology. The conversion of a lactone to an ether has been accomplished by hydride reduction to a diol followed by cyclization by way of a monotosylate4 or other activated ester.5