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.
Lamentations on Chemistry 
I think from an academic total synthesis point of view, it’s still quite used and useful.
From an industrial POV, I dunno. ADmix is sold by Aldrich at $2/gram per 50 gram bottle; I assume that the price will fall at least a little.
I suppose what I should have asked is this: is there a better means of epoxidation or dihydroxylation today? I remember getting grilled on the mechanism on my preliminary orals exam. Luckily, I had worked through the mechanism the night before.
I believe there are a larger variety of enantioselective epoxidations other than the SAE now — Jacobsen and Shi come to mind immediately, and I’m sure I’m forgetting something.
As far as dihydroxylation, no, nothing comes to mind.
It makes a difference for a pharma company developing an asymmetric route to their drug candidate. Now they can buy the catalyst on the cheap from China, without worrying about IP position. If you have a key step which depends on licencing negotiation with another company that has patent-backed monopoly on sale of the chiral catalyst and its use, you can end up paying through the nose.
I had a conversation with Paul Rider back when he was a boss of Merck process. He said he gave about 30% time to his good chemists to play with methodology hobby projects for publication purposes as long as they were at least tangentially related to their main job.
This resulted an impressive stream of quality methodology papers, with Paul on all of them as a co-author… and supposedly kept people satisfied while making hiring top candidates easier because of the reputation. But there was another agenda: they filled patents on all their methodology before writing a paper. Not that they would want to exclude other groups but they did not want to be prevented by someone else from using their own stuff in the future.
And he gave me an example of an original paracyclphane chiral phosphine that they developed as a shobby project that gave 94% ee for their important intermediate. In the end they opted for using off-the shelf BINAP-based catalyst from Takasago that gave them 96% ee But they were able to bargain down the price of the catalyst simply by pointing out that they had a doable fall-back alternative.
Asym epoxidation process alternatives:
1)Asym epoxidation of allylic alcohols with Ti(iV) tartratecomplex, also from Sharpless. It requires allylilc substrates.
2) Shi epoxidation – not very suitable for scale-up (huge ocatalyst loadings – typically 30 mol% and problems with removing spent catalyst by nonchromatographic methods) and the sugar-derived catalyst is really expensive for the L-enantiomer.
3) Jacobsen asym epoxidation: It works great for Z styrenes and their cyclic variants (chromenes, indenes) but the substrate scope is pretty narrow. It is complementary to asym dihydroxylation (the substrates that work poorly for Jacobsen epoxidation often perform great in Sharpless AD and vice versa)
4) Jacobsen kinetic resolution of epoxides: very useful for hydrolysis of monosubst oxiranes but limited in scope. The startiing racemic material has to be very cheap and easily separable from the diol (by distillation). This method is great for producing optically active small synthons like propylene oxide, epichlorohydrine etc but it is not suitable for a late-stage intermediate.