Editing Sharpless asymmetric dihydroxylation (section)

== Regioselectivity ==
In general Sharpless asymmetric dihydroxylation favors oxidation of the more electron-rich alkene (scheme 1).<ref>{{Cite journal|title = Selective asymmetric dihydroxylation (AD) of dienes|date = September 1992|first = D.|last = Xu|last2 = Crispino|first2 = G. A.|last3 = Sharpless|first3 = K. B.|journal = [[J. Am. Chem. Soc.]]|volume = 114|pages = 7570–7571|doi = 10.1021/ja00045a043|issue = 19}}
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[[Image:SAD scheme 1.png|600px|center|SAD scheme 1]]

In this example SAD gives the diol of the alkene closest to the (electron-withdrawing) para-methoxybenzoyl group, albeit in low yield. This is likely due to the ability of the aryl ring to interact favorably with the active site of the catalyst via π-stacking. In this manner the aryl substituent can act as a directing group.<ref name=":0">{{Cite journal|title = The application of a mechanistic model leads to the extension of the Sharpless asymmetric dihydroxylation to allylic 4-methoxybenzoates and conformationally related amine and homoallylic alcohol derivatives.|date = November 1995|first = E. J.|last = Corey|last2 = Guzman-Perez|first2 = Angel|last3 = Noe|first3 = Mark C.|journal = [[J. Am. Chem. Soc.]]|volume = 117|pages = 10805–10816|doi = 10.1021/ja00149a003|issue = 44}}</ref>

[[Image:SAD scheme 2.png|600px|center|SAD scheme 2]]