Synthesis of Terpinolene A Retrosynthetic Analysis

Terpinolene is a food additive that has an odor of lime or citrus fruits. We would like to know how to synthesize terpinolene from readily available, inexpensive precursors, and we will approach its 

The first thing we notice is that the target molecule has an isopropylidene unit. This certainly looks like a candidate for a Grubbs disconnect. 

We know that we can synthesize an alkyl bromide from an alcohol with PBt3. 

The last functional group interconversion gives us the six-membered ring we need. The next step in our retrosynthetic scheme is a Diels-Alder disconnect. 

Functional Group Interconversions step 2 step 3 step 4 

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