Could someone help out with this question. Im stuck on it. Thanks
When (R)-butan-2-ol is treated with TsCl in pyridine and the tosylated alcohol is treated with sodium chloride in acetone, the resulting product is:
A) (R)-2-iodobutane
B) (S)-2-iodobutane
C) 2-iodobutane (racemic)
D) 1-butane
E) None of these
I think its choice B or C, but im not sure.
When (R)-butan-2-ol is treated with TsCl in pyridine and the tosylated alcohol is treated with sodium chloride in acetone we expect an inversion of the chiral centre and a 2-chlorobutane to be formed. There is no 2-chlorobutane in the list so
E)none of these.
There will also be some elimination reaction to form butene, but again there is no butene in the list.
To determine the resulting product in this reaction, we need to analyze the given steps and understand the mechanism involved.
Step 1: (R)-butan-2-ol treated with TsCl in pyridine.
In this step, (R)-butan-2-ol reacts with TsCl (tosyl chloride) in the presence of pyridine as a base. This reaction involves the substitution of the hydroxyl group with the tosyl group (tosylation).
The resulting product is (R)-butan-2-yl tosylate (tosylate group attached to the carbon next to the hydroxyl group).
Step 2: Tosylated alcohol treated with sodium chloride in acetone.
In this step, the tosylated alcohol reacts with sodium chloride in the presence of acetone. This reaction is an elimination reaction, referred to as the Williamson ether synthesis. It involves the substitution of the tosyl group with chloride, leading to the formation of an alkyl chloride.
The resulting product is 2-chlorobutane (chloride group attached to the carbon next to the hydroxyl group).
Now, let’s analyze the options based on the given steps:
A) (R)-2-iodobutane: This product is not formed in the given reaction steps, as there is no step involving the introduction of an iodine atom.
B) (S)-2-iodobutane: This product is also not formed in the given reaction steps, as there is no step involving the introduction of an iodine atom.
C) 2-iodobutane (racemic): This product is not formed in the given reaction steps. As seen from the steps, the final reaction is an elimination reaction, and it does not involve the introduction of iodine.
D) 1-butane: This product is not formed in the given reaction steps. The result of the reaction is the substitution of the hydroxyl group and the subsequent elimination of the tosyl group, leading to the formation of a 2-chlorobutane.
E) None of these: Based on the analysis above, this option seems to be the correct choice, as none of the given options match the product formed.
Therefore, the correct answer is option E) None of these.