Textbook Question
Predict the product of the following sulfonylation reactions.
(c)
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12. Alcohols, Ethers, Epoxides and Thiols
Leaving Group Conversions - Sulfonyl Chlorides
2:37 minutesProblem 58a
Textbook Question
Starting with (R)-1-deuterio-1-propanol, how could you prepare
a. (S)-1-deuterio-1-propanol?
Verified step by step guidance1
Identify the stereochemistry of the starting material, (R)-1-deuterio-1-propanol. The (R) configuration indicates the specific spatial arrangement of the substituents around the chiral center.
To convert the (R)-1-deuterio-1-propanol to its enantiomer, (S)-1-deuterio-1-propanol, you need to invert the stereochemistry at the chiral center. This can be achieved through a two-step process: conversion to an intermediate and subsequent inversion.
Step 1: Convert the alcohol group (-OH) into a good leaving group. This can be done by reacting (R)-1-deuterio-1-propanol with a reagent like p-toluenesulfonyl chloride (TsCl) in the presence of a base (e.g., pyridine) to form the corresponding tosylate. The tosylate group is an excellent leaving group.
Step 2: Perform an SN2 reaction with a nucleophile (e.g., hydroxide ion, OH⁻) to replace the tosylate group with a hydroxyl group. The SN2 mechanism involves a backside attack, which inverts the stereochemistry at the chiral center, resulting in (S)-1-deuterio-1-propanol.
Finally, confirm the stereochemistry of the product using spectroscopic methods (e.g., NMR or optical rotation) to ensure the desired (S)-configuration has been achieved.
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Video duration:
2mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Stereochemistry
Stereochemistry is the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In this context, it is crucial to understand the difference between enantiomers, which are molecules that are mirror images of each other, such as (R)- and (S)-1-deuterio-1-propanol. The ability to manipulate these configurations is essential for synthesizing specific stereoisomers.
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Chiral Centers
A chiral center, often a carbon atom, is bonded to four different substituents, leading to non-superimposable mirror images. In the case of 1-deuterio-1-propanol, the chiral center's configuration determines whether the molecule is in the (R) or (S) form. Understanding how to identify and modify chiral centers is key to synthesizing the desired stereoisomer.
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Reactions for Synthesis
Various chemical reactions can be employed to convert one stereoisomer into another, such as inversion reactions or specific chiral catalysts. For example, using a suitable reagent that selectively reacts with the (R)-1-deuterio-1-propanol can lead to the formation of (S)-1-deuterio-1-propanol. Familiarity with these synthetic pathways is essential for achieving the desired product.
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