Show how each of the following compounds can be prepared using the given starting material, any needed inorganic reagents, and any ­organic compound that has no more than four carbons:
b.

Verified step by step guidance

1. Step 1: Begin with the starting material, acetylene (HC≡CH). Perform a hydroboration reaction using diborane (B2H6) to convert the alkyne into an alkene. This reaction will yield ethene (CH2=CH2).
2. Step 2: Perform a Markovnikov addition of HBr to ethene. This reaction will produce bromoethane (CH3CH2Br).
3. Step 3: React bromoethane with magnesium in dry ether to form the Grignard reagent, ethylmagnesium bromide (CH3CH2MgBr).
4. Step 4: Prepare propanal (CH3CH2CHO) by oxidizing propanol (CH3CH2CH2OH) using PCC (pyridinium chlorochromate). Propanol is an organic compound with no more than four carbons.
5. Step 5: React the Grignard reagent (CH3CH2MgBr) with propanal (CH3CH2CHO) to form the desired product, 2-bromo-3-methylbutane (CH3CH2CHCH3 with a Br substituent). This reaction involves nucleophilic addition followed by protonation.

Key Concepts

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. Understanding the functional groups present in both the starting material and the target compounds is essential for determining the appropriate reactions and reagents needed for synthesis.

Reaction Mechanisms

Reaction mechanisms describe the step-by-step process by which reactants are converted into products. Familiarity with common mechanisms, such as nucleophilic substitution or elimination reactions, is crucial for predicting how to transform the starting material into the desired compounds using the specified reagents.

Synthesis Strategies

Synthesis strategies involve planning a series of chemical reactions to construct a target molecule from simpler starting materials. This includes selecting appropriate reagents, considering reaction conditions, and ensuring that the overall pathway is efficient and feasible, especially when limited to organic compounds with four or fewer carbons.