|Chapter 15: Alcohols, Diols and Thiols|
Hydroxylation of Alkenes
Reaction Type : Electrophilic Addition
What other reaction is commonly used as a functional group test for alkenes ? ANSWER
What is the oxidation state of the osmium in osmium tetroxide ? ANSWER
Is the osmium oxidised or reduced during the formation of the osmate ester ? ANSWER
What is the oxidation state of the potassium permanganate ? ANSWER
The p electrons in the alkene act as a nucleophile forming a favourable 5 membered ring as a cyclic osmate ester as an intermediate. Note the origin of the cis stereochemistry.
The hydroxide liberates the cis-diol and the reduced osmium species.... this would then be reoxidised by the peroxide co-oxidant.
|© Dr. Ian Hunt, Department of Chemistry, University of Calgary|