Page 106 - Pharm.Org.Chem-I 02-06-05-101
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Stereochemistry of the anti hydroxylation of alkenes
• Anti hydroxylation of cis-2-butene gives racemic modification of
2,3-dihydroxybutane.
• While anti-hydroxylation of trans-2-butene gives meso 2,3-dihydroxy-
butane.
Summary of Stereochemistry of Br2addition, syn
and anti hydroxylations
Addition of Addition Start Product
type racemic mixture
Br2 meso compound
Anti- (Z)-2-butene racemic mixture
Br2 addition (E)-2-butene meso compound
(Z)-2-butene meso compound
Peroxy acid followed Anti- (E)-2-butene
by cleavage of addition
epoxide in acidic or
alkaline medium Anti-
addition
Cold dilute KMnO4
Anti-
addition
Syn addition (Z)-2-butene
Cold dilute KMnO4 Syn addition (E)-2-butene racemic mixture
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