CHEM 203 Lecture Notes - Lecture 15: Syn And Anti Addition, Peroxide, Racemic Mixture
Document Summary
Stereochemical aspects of the hydroboration/oxidation reaction: the case of more complex olefins such as, e. g. , 1-methylcyclohexene: The hydroboration reaction as a strictly syn addition: b and h atoms must necessarily add from the same face of the system. Steric interaction: the energetically unfavorable compression of independent (= not bonded) atoms/groups of atoms against each other. The oxidation of boranes as a substitution reaction. Stereochemical aspects of the oxidation of alkylboranes to alcohols with h2o2 / aq. Example: the alkylborane obtained upon hydroboration of 1-methylcyclohexene could undergo oxidation (a substitution reaction) to give: Lecture of oct 6: 2 hypothetical retention of con guration hypothetical inversion of con guration. B (racemic) diastereomers hypothetical loss of con guration mixture of diastereomers. General mechanism of the oxidation of boranes with h2o2 / naoh (aq. : deprotonation of h2o2 and formation of the hydroperoxy anion: Ho-h + o oh oxidation state of peroxy o"s = 1 pka 16 hydroperoxy anion.
