Allylic amides, dihydroxylation

The chelating nature of the diamine precludes osmate ester hy-droysis in situ and means that the oxidation of an alkene requires 1 equiv of osmium tetroxide, followed by a step to release the glycol. However, the use of catalytic amounts of transition metal in the directed dihydroxylation of allylic amides was shown to be possible (eq 31) by using a monodentate amine (quinuclidine, which is released in situ from quinuclidine-A(-oxide). These conditions are catalytic in osmium but generally exhibit a less powerful directing effect than stoichiometric osmium tetroxide and TMEDA. 

Additionally, 1,2-dihydroxyethylene dipeptide analogues without the C-terminal carboxylic acid have been used to obtain aspartyl proteases inhibitors.[641 These efforts include stereoselective alkylation of imines, one-pot reductive amination of epoxy ketones, ring opening of epoxides with sodium azide, diastereoselective dihydroxylation of allylic amines, and enzymatic resolution and stereocontrolled intramolecular amidation. 

Moreover, and more importantly for practical purposes, functionalized olefins with nearly all kinds of substituents attached to the olefin can be dihydroxylated. Thus, acrylic acid esters, unsaturated amides and ketones, dienes, enynes, vinyl silanes, acrolein acetals, and allylic halides, as well as allylic ethers and sulfur-... 

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