Trans Hydroxylation of Alkenes

Alkenes are hydroxy lated syn by either 0s04 or Mn04. In both cases the intermediates are cyclic esters, cleavage of which does not involve breaking the C-G bonds, 

Trans hydroxylation of an alkene involves sequential conversion to an oxirane (epoxide), and its conjugate acid, followed by nucleophilic opening of the oxirane by water 

In this reaction the C=C double bond acts as a nucleophile, and in most acyclic or monocyclic molecules oxygen is added with equal facility to the top or bottom face of the alkene. Oxiranes are the most reactive ethers, and are readily susceptible to nucleophilic attack, which results in ring opening. This is in contrast to diethyl ether (ethoxyethane), which is inert even in the presence of, for example, LiAlH4. Likewise, 1,2-dimethylcyclohexene (27) reacts with peroxy acids to give cis-1,2-dimethylcyclohexene oxide (28). 

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