A cyclic iodonium ion is the first intermediate in both the Woodward and Prevost Reactions, which yield the syn and anti versions of these compounds, respectively.  
One of these compounds forms an intermediate in the McMurry Reaction.  A cyclic iodonium ion is the first intermediate in both the Woodward and Prevost Reactions, which yield the syn and anti versions of these compounds, respectively.  These compounds form ketones in the Pinacol Rearrangement, and osmium-based catalysts are used both the Upjohn and Sharpless Dihydroxylations that make these compounds.  For 10 points, identify this class of molecules characterized by the presence of two -OH groups.
One of these compounds forms an intermediate in the McMurry Reaction.  
{diol}s or {dialcohols} (or {glycols})