I noticed that a number of the Sharpless US patents for dihydroxylation processes would appear to be expired. For example, US 5126494, US 4965364, US 5227543, US 5260461, US 4871855, etc. 

I wonder how useful this chemistry is today? It was a minor sensation back when I was in grad school.  Of course, grad students and profs didn’t worry about patent coverage then.