Q77E

Question


6-Methyl-5-hepten-2-one is a constituent of lemongrass oil. How could you synthesize this substance from methyl 4-oxopentanoate?



Methyl 4-oxopentanoate

Step-by-Step Solution

Verified
Answer

The synthesis of the given reaction involves protecting the ketone, converting the ester into an aldehyde, using Wittig reaction to introduce a substituted double bond and the last step is deprotecting the ketone to synthesize the given product.

1Step-by-step Solution Step 1: Wittig reaction


The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagentWittig reactions are most commonly used to convert aldehydes and ketones to alkenes. The geometry of the resulting alkene depend upon the reactivity of the ylide. Ylides can be synthesized from an alky halide and trialkyl phosphine.



Wittig reaction



2Step 2: Synthesis of given substance


The synthesis of the given reaction involves following sequence: 

1. Protecting the ketone

2. Converting the ester into an aldehyde

3. Using Wittig reaction to introduced a substituted double bond.

4. The last step is deprotecting the ketone




Synthesis of 6-methyl-5-hepten-2-one