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Starting with trans-2-butene, show how to prepare meso-2,3-butanediol.

a) A single-step reaction
b) Through a multi-step reaction
c) Requires a catalyst
d) Not possible from trans-2-butene

1 Answer

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Final answer:

Meso-2,3-butanediol can be synthesized from trans-2-butene through a multi-step procedure involving hydroboration-oxidation without a catalyst, resulting in an optically inactive diol due to its symmetry.

Step-by-step explanation:

To synthesize meso-2,3-butanediol from trans-2-butene, we can conduct a multi-step reaction. First, we perform a hydroboration-oxidation reaction.

  • Add BH3 (borane) to the trans-2-butene in the presence of THF (tetrahydrofuran) as a solvent to achieve anti-Markovnikov hydroboration.
  • Oxidize the resulting trialkylborane with H2O2 (hydrogen peroxide) in a basic aqueous solution to form the alcohol.

This reaction will produce a racemic mixture of 2,3-butanediol. However, due to the symmetry of meso-2,3-butanediol, which means it has a plane of symmetry, the resulting diol will be optically inactive, effectively functioning as the meso compound.
This process requires no catalyst, and it is not a single-step process, nor does it proceed via a Diels-Alder or similar cycloaddition reaction.

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