Which reagents reagents to choose?
The transformation shown below can be accomplished in TWO reaction steps. From the following list, select the two reagents (or sets of reagents) which would most effectively bring about this conversion. Reagents:
1. Conc H2SO4/heat
2. CN-
3. KMnO4
4. (i) CH3MgI (ii) H3O+
5. PBr3
6. (i) BH3 (ii) H2O2
7. CH3CH2O-/CH3CH2OH
8. H2O/H+
9. OH-/H2O
10. (i) O3 (ii) Zn
11. NaBH4
12. HCl
13. KI
14. Na
15. CH3CH2Br
Please enter the reagent number (from the above list) for each of the two steps in the following synthesis:
Step 1:
Step 2:
CH3CHOHCH3 (Secondary Alcohol) ->(Step1) -> (Step 2) Tertiary Alcohol
Thank you
duplicate
To convert the secondary alcohol CH3CHOHCH3 to a tertiary alcohol, we need to perform two reaction steps. Let's go through the options and choose the appropriate reagents for each step:
Step 1: The primary goal of this step is to convert the secondary alcohol into a carbocation intermediate. To achieve this, we can use an acid-catalyzed dehydration. The reagents that would be suitable for this step include:
- Option 1: Conc H2SO4/heat
- Option 7: CH3CH2O-/CH3CH2OH
- Option 12: HCl
Since the first two options have reagents that could potentially lead to other reactions or side-products, we will choose option 1, Conc H2SO4/heat, as it is a common method for dehydrating alcohols to form carbocations.
Step 2: In this step, we need to convert the carbocation intermediate (formed in step 1) into a tertiary alcohol. To achieve this, we can use a nucleophile that can attack the carbocation and donate a pair of electrons. Suitable options for this step include:
- Option 4: (i) CH3MgI (ii) H3O+
- Option 6: (i) BH3 (ii) H2O2
- Option 11: NaBH4
While options 4 and 6 involve the addition of nucleophiles, they also include additional steps that could lead to undesired side reactions. Therefore, we will choose option 11, NaBH4, as it is a common reducing agent used to convert carbocations to alcohols.
So, the reagent numbers for each step would be:
Step 1: Option 1 (Conc H2SO4/heat)
Step 2: Option 11 (NaBH4)
Using these reagents in the two reaction steps should effectively bring about the conversion of CH3CHOHCH3 to a tertiary alcohol.