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Reaction of (R)-2-bromo-1-flourobutane with Sodium Cyanide in Ethanol (aq)

Pure (R)-2-bromo-1-flourobutane reacts with sodium cyanide in aqueous ethanol to form pure (R)-2-flouromethylbutanenitrile.

1) What is the probable mechanism of this reaction? Explain your reasoning.

2) Based on your choice of mechanism, explain how both the substrate and the product can have R configuration?

3) What will be the effect on the rate of this reaction of each of the following changes? Explain why in each case

a) Doubling the concentration of sodium cyanide?

b) Using dimethylsulfide in place of aqueous ethanol as the solvent?

c) Using a racemic rather than an enantiomerically pure substrate?

Solution Preview

To assess by which mechanism a substitution reaction takes place, we must look at 3 things:

1. Carbon type (primary, secondary, tertiary)
2. Nucleophile (is it a good (negatively charged) or bad (neutral))
3. Solvent (polar, non-polar)

For this reaction we have ourselves a secondary carbon, which tells us nothing.

We ...

Solution Summary

The reaction of (R)-2-bromo-1-flourobutane with Sodium Cyanide in ethanol (aq) is analyzed. The reaction mechanism is determined through which the R configuration can be found.