In 1997, Sinaÿ and co-workers reported an alternative route to the synthesis (shown below) that did not involve cleavage of the bond at the anomeric position (the glycosidic bond).  In this case, the major product formed had maintained its original configuration at the anomeric position.
Sinaÿ proposed this reaction went through the following transition state:
Sinaÿ also discovered that titanium (IV) derivatives such as [TiCl(OiPr)] worked in the same reaction as a milder version of the Lewis acid, i-BuAl, which goes through a similar transition state involving the retention of configuration at the anomeric center.
In 1988, Adam reported a modification of the reaction that used catalytic amounts of palladium (II) salts, which brought about the same conversion of enol ethers into carbosugars in a more environmentally friendly manner.